Technical Field

This invention relates to materials and methodologies for the alleviation of herpes virus infections. More specifically, it relates to compositions containing a polypeptide comprised of an immunogenic epitope of VP16, including VP16 and fragments thereof, and to methods for preparing the polypeptides for the composition.

Background

The herpes viruses include the herpes simplex viruses (HSV) , comprising two closely related variants designated types 1 (HSV-1) and 2 (HSV-2) . Herpes simplex virus (HSV) is a prevalent cause of genital infection m humans, with an estimated annual incidence of 600,003 new cases and with 10 to 20 million individuals experiencing symptomatic chronic recurrent disease. The asymptomatic subclinical infection rate may be even higher. Using a type-specific serological assay, researchers showed that 35% of an unselected population of women attending a health maintenance organization clinic in Atlanta had antibodies to HSV type 2 (HSV-2) . ^" though continuous administration of antiviral drugs s-_:_ ^■ . as acyclovir ameliorates the severity of acute HSV disease and reduces the frequency and duration of recurrent episodes, such che otherapeutic intervention does not abort the establishment of latency nor does it alter the status cf the latent virus. As a consequence, the recurrent

disease pattern is rapidly reestablished upon cessation of drug treatment. Since the main source of virus transmission arises from recrudescent disease, any approach to impact the rate of infection must ultimately require a vaccine strategy. Thus, it is a matter of great medical and scientific interest to provide safe and effective vaccines for humans to prevent HSV infection, and where infection has occurred, therapies for the disease.

HSV is a double stranded DNA virus. aving'a genome of about 150 to 160 kbp packaged within an icosahedral capsid surrounded by a membrane envelope. The viral envelope includes at least seven virus-specific glycoproteins, including gB, gC, gD, gE, and gG, where gB and gD are cross-reactive between types 1 and I . One approach to vaccine therapy has been the use of isolated glycoproteins, which have been shown to provide protection when injected into mice subsequently challenged with live virus.

The VP16 gene product is associated with the virion. tegument, located between the capsid and the envelope (See Fig. 1). VP16, which is a virion stimulatory factor, -is an abundant protein with some 500 to 1000 copies per virion. It has been alternately named ICP25, Vm 65, and the α-trans-inducing factor (αTIF) . The majority of studies on VP16 have explored its role in the trans-activation of the "immediate early genes" in HSV replication. In view of the internal location of VP16 in the virion, and the current state of knowledge concerning the mode of HSV replication, VP16 would not be expected to be a good candidate for use in treatment of HSV infections.

Relevant Literature

Spear and Roizman (1972) disclose the electrophoretic separation of proteins in purified HSVl. McLean et al. (1982) discloses a monoclonal antibody which ^' putatively interacts with VP16 from HSVl and HSV2.

Eberle et al. (1984) , discloses studies on antibody response to HSV components during primary and recurrent genital HSV-2 infections.

Campbell et al. (1984) , putatively discloses a DNA sequence encoding VmW65 of HSVl, and identifies Vm 65 as the major tegument virion component which trar.ε- activates HSV immediate-early (IE) transcription.

Pellett et al. (1985) discloses the expression of cloned HSVl α-TIF encoding sequence in transient expression systems.

Triezenberg et al. (1988) , discloses a putative amino acid sequence for HSVl VP16, and deletion mutants thereof.

McGeoch et al. (1988) presents a DNA sequence of the long unique region (U;.) of HSV-1 strain 17. This region includes a segment which putatively encodes, in gene UL48, the mejor tegument protein (which is an activator of transcription of IE genes in the newly infected cell) .

References

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Campbell et al. (1984), J. Mol. Biol. 180:1. Chakrabarti et al. (1985), Mol. Cell Biol.

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Disclosure of the Invention

The instant invention results from the discovery that a tegument polypeptide of HSV, VP16, is immunogenic and ameliorates the disease caused by HSV infection. Thus, the invention includes compositions which are comprised of an immunogenic epitope of HSV VP16 which are useful for the treatment of HSV infection, polypeptides used in these compositions, methods of treating HSV infection using these compositions, and methods of preparing these compositions and immunogenic polypeptides used in these compositions; also included are vectors comprised of polynucleotide sequences encoding these polypeptides, and cells transformed with the vectors.

Accordingly, one aspect of the invention is a composition for treatment of an individual for herpes simplex virus (HSV) infection comprising an isolated immunogenic polypeptide containing an immunogenic epitope of HSV VP16, wherein the polypeptide is present in a pharmacologically effective dose in a pharmaceutically acceptable excipient.

Another aspect of the invention is a composition comprised of recombinant vaccinia virus, wherein the virus is comprised of a sequence encoding an immunogenic polypeptide selected from HSV VP16, truncated HSV VP16, and mutants thereof, wherein the polynucleotide encoding the immunogenic polypeptide is operably linked to a control sequence.

Yet another aspect of the invention is a method of producing a composition for treatment of HSV infection comprising:

(a) providing an immunogenic polypeptide comprised of an immunogenic epitope of HSV VP16;

(b) formulating the polypeptide in a pharmaceutically acceptable excipient.

Another aspect of the invention is a composition produced by the above method.

Still another aspect of the invention is a method of treating an individual for HSV infection comprising administering to the individual the above- described compositions.

10 An additional aspect of the invention is a recombinant polynucleotide encoding a polypeptide comprised of an immunogenic epitope of HSV-2 VP16.

Yet another aspect of the invention is a recombinant vector comprised of the above-described

15 polynucleotide.

Yet. another aspect of the invention is a recombinant expression system comprising an open reading frame (ORF) of DNA encoding a polypeptide comprised of an immunogenic epitope of HSV-2 VP16, wherein the ORF is

20 operably linked to a control sequence compatible with a desired host.

Another aspect of _the invention is a host cell transformed with the recombinant expression system cf claim 38.

25 Still another aspect of the invention is a method of producing an immunogenic polypeptide for use in the treatment of HSV infection, the method comprising:

(a) providing the above-described host cell;

(b) incubating the host c ^* . ^: l under conditions

30 which allow expression of the polypeptide; and

(c) isolating the expressed polypeptide from the host cell.

- D

Still another aspect of the invention is an immunogenic polypeptide for use in the treatment of HSV infection, produced by the above-described method.

Brief Description of the Drawings

Fig. 1 is a schematic drawing of an HSV virion.

Fig. 2 shows the putative amino acid sequences of HSV-l VP16 and HSV-2 VP16.

Fig. 3 shows the nucleotide sequence encoding HSV-2 VP16, and the amino acids encoded therein.

Fig. 4 is a map showing some significant features of the vector pAC373, of pVL985, and the sequence encoding the n-terminal amino acids of the polyhedrin gene.

Fig. 5 is a map showing some significant features of the vector pHS225.

Fig. 6 is a copy of Fig. 4 of WO88/02634, which presents the nucleotide sequence encoding HSV gB2 , and the amino acids encoded therein.

Fig. 7 is a map showing some significant features of the vector pHS218.

Fig. 8 is a map showing some significant features of the vector pBCB07.

Fig. 9 is a map showing some significant features of the vector pVACC-gB2.

Fig. 10 is a schematic showing the contents of wells in an antibody titer study.

Fig. 11 is a bar graph showing the titer of HSV specific complement dependent neutralizing antibody titers resulting from immunization with vv-gB2 and w- VP16.

Fig. 12 is a graph showing the time course of protection resulting from immunization with w-gB2.

Fig. 13 is a graph showing the time course of protection resulting from immunization with W-VP16.

Fig. 14 is a graph showing the time course of protection resulting from immunization with w-gB2 , w- VP16, and w-gB2 + W-VP16.

Modes for Carrying Out the Invention

The following terminology is used herein.

The term "polypeptide" refers to a polymer of amino acids and does not refer to a specific length of the product; thus, peptides, oligopeptides, and proteins are included within the definition of polypeptide. This term also does not refer to or exclude post-expression modifications of the polypeptide, for example, glycosylations, acetylations, phosphorylations and the like. Included within the definition are, for example, polypeptides containing one or more analogs of an amino acid (including, for example,unnatural amino acids, etc.), polypeptides with substituted linkages, as well as other modifications known in the art, both naturally occurring and non-naturally occurring.

The term "isolated polypeptide" refers to a polypeptide whioh is substantially free of other HSV viral components, particularly polynucleotides. A polypeptide composition is "substantially free" of another component if the weight of the polypeptide in the composition is t least 70% of the v ght of the polypeptide and other component co :.-- ed, more preferably at least about 80%, still more preferably about 90%, and most preferably 95% or greater. For example, a composition containing 100 μg/mL VP16 and only 3 μg/mother HSV components (e.g., DNA, lipids, etc.; is substantially free of "other HSV viral components," and

thus is a composition of n isolated polypeptide within the scope of this definition. Similarly, some compositions of the invention comprise an isolated VP16 polypeptide in combination with one or more isolated HSV glycoproteins, e.g., gB, gC, gD, and the like.

A "recombinant .polynucleotide" intends a polynucleotide of genomic, cDNA, semisynthetic, or synthetic origin which, by virtue of its origin or manipulation: (1) is not associated with all or a portion of a polynucleotide with which it is. associated in. . nature, (2) is linked to a polynucleotide other than that to which it is linked in nature, or (3) does not occur m nature.

A "polynucleotide" is a polymeric form of nucleotides of any length, either ribonucleotides or deoxyribonucleotides. This term refers only to the primary structure of the molecule. Thus, this term includes double- and single-stranded DNA and RNA. It also includes known types of modifications, for example, labels which are known in the art, methylation, "caps", substitution of one or more of the naturally occurring nucleotides with an analog, internucleotide modifications such as, for example, those with uncharged linkages (e.g., phosphorothioates, phosphorodithioates, etc.) , those containing pendant moieties, such as, for example proteins (including for e.g., nucleases, toxins, antibodies, signal peptides, poly-L-lysine, etc.) ,those with intercalators (e.g., acridine, psoralen, etc.) , those containing chelators (e.g. ,metals, radioactive metals, etc.), those containing alkylatorε, those with modified linkages (e.g., alpha anomeric nucleic acids, etc.) , as well as unmodified forms of the polynucleotide.

"Recombinant host cells", "host cells", "cells", "cell lines", "cell cultures", and other such terms denoting microorganisms or higher eukaryotic cell lines cultured as unicellular entities refer to cells which can be or have been, used as recipients for a recombinant vector or other transfer polynucleotide, and include the progeny of the original cell which has been transfected. It is understood that the progeny of a single parental cell may not necessarily be completely identical in morphology or in genomic or total DNA complement as the original parent, due to natural, accidental, or deliberate mutation.

A "replicon" is any genetic element, e.g., a plasmid, a chromosome, a virus, a cosmid, etc. , that behaves as an autonomous unit of polynucleotide replication within a cell; i.e., capable of replication under its own control.

A "vector" is a replicon further comprising sequences providing replication and/or expression of the open reading frame.

"Control sequence" refers to polynucleotide sequences which are necessary to effect the expression of coding sequences*to which they are ligated. The nature of such control sequences differs depending upon the host organism; in prokaryotes, such control sequences generally include promoter, riboεomal binding site, and terminators; in eukaryotes, generally, such control sequences include promoters, terminators and, m some instances, enhancers. The term "control sequences" is intended to include, at a minimum, all components whose presence is necessary for expression, and may also include additional components whose presence is

advantageouε, for example, leader sequences which govern secretion.

A "promoter" is a nucleotide sequence which is comprised of consensus sequences which allow the binding of RNA polymerase to the DNA template in a manner such that mRNA production inititiates at the normal transcription initiation site for the adjacent structural gene.

10 "Operably linked" refers to a juxtaposition wherein the components so described are in a relationship permitting them to function in their intended manner. A control sequence "operably linked" to a coding sequence is ligated in such a way that expression of the coding

15 sequence is achieved under conditions compatible with the control sequences.

An "open reading frame" (ORF) is a region of a polynucleotide sequence which encodes a polypeptide; this region may represent a portion of a coding sequence or a

20 total coding sequence.

A "coding sequence" is a polynucleotide sequence which is transcribed into mRNA and/or translated into a polypeptide when placed under the control of appropriate regulatory sequences. The boundaries of the m m coding sequence are determined by a translation start codon at the 5 '-terminus and a translation stop codon at the 3'-terminus. A coding sequence can include but is not limited to mRNA, DNA (including cDNA) , and recombinant polynucleotide sequences.

As used herein, "epitope" referε to an antigenic determinant of a polypeptide. An epitope could compriεe 3 amino acids in a spatial conformation which iε unique to the epitope. Generally an epitope consists of at least 5 such amino acids, and more usually, 35

consists of at about 8 to 10 such amino acids. Methods of determining the spatial conformation of such amino acids are known in the art, and include, for example, x- ray crystallography and 2-dimensional nuclear magnetic reference.

An "immunogenic epitope" is an epitope in a polypeptide that elicits a cellular and/or humoral immune response; the response may be elicited by the polypeptide alone, or may require the presence of a carrier in the presence or absence of an adjuvant.

An epitope is the "immunologic equivalent" of another epitope in a designated polypeptide when it has the amino acid sequence and conformation which allows it to cross-react with antibodies which bind immunologically to the epitope in the designated polypeptide.

As used herein, an epitope of a designated polypeptide denotes epitopes with the same amino acid sequence as the epitope in the designated polypeptide, and immunologic equivalents thereof.

A polypeptide which is "comprised of an immunogenic epitope of HSV VP16" is a polypeptide which containε a sequence of amino acids of HSV VP16 of at least the number to form the immunogenic epitope, usually at least about five amino acids, more usually at least about 8 amino acids, and even more usually about 10 or more amino acids; the maximum size is not critical. The amino acid sequence from HSV VP16 ray be linked at the amino terminus and/or carboxy term.r.s to another polypeptide (e.g., a carrier protein;, either by covalent attachment or by expresεing a fused polynucleotide to form a fusion protein. If desired, one may insert cr attache multiple repeats of the epitope, and/or incorporate a variety of epitopes. The carrier protein

ay be derived from any source, but will generally be a relatively large, immunogenic protein such as BSA, KLH, or the like. If desired, one may employ a substantially full-length VP16 protein as the carrier, multiplying the number of immunogenic epitopes. Alternatively, the amino acid sequence from HSV VP16 may be linked at the amino terminus and/or carboxy terminus to a non-HΞV VP16 amino acid sequence, thus the polypeptide would be a "fusion polypeptide". Analagous types of polypeptides may be constructed using epitopes from other designated viral proteins.

A "mutant" of a designated polypeptide refers to a polypeptide in which the amino acid sequence of the designated polypeptide has been altered by the deletion or substitution of one or more amino acids in the sequence, or by the. addition of one or more amino acids to the sequence. Methods by which mutants occur (for example, by recombination) or are made (for example, by site directed mutagenesis) are known in the art.

"Transformation" refers to the insertion of an exogenous polynucleotide into a host cell, irrespective of the method used for the insertion, for example, direct uptake, transduction (including viral infection) , f- mating or electroporation. The exogenous polynucleotide may be maintained as a non-integrated vector, for example, a plasmid or viral genome, or alternatively, may be integrated into the host genome.

An "individual" refers to a vertebrate, particularly a member of a mammalian species, and includeε but is not limited to domestic animals, εportε animalε, and primates, including humans.

As used herein, . "treatment" refers to any of (i) the prevention of infection or reinfection, as in a

traditional vaccine, (ii) the reduction or elimination of symptoms, and (iii) the substantial elimination of the virus. Treatment may be effected prophylactically (before or prior to infection) or therapeutically (during or following infection) .

The term "effective amount" refers to an amount of epitope-bearing polypeptide sufficient to induce an immune response in the subject to which it is administered. The immune response may comprise, without limitation, induction of cellular and/or humoral immunity. Preferably, the effective amount is sufficient to effect treatment, as defined above. The exact amount necesεary will vary from εubject to subject, depending ont he species, age, and general condition of the subject, the severity of the condition being treatea, the particular polypeptide selected and its mode of administration, etc. Thus, it is not possible to specify an exact effective amount. However, the appropriate effective amount may be determined by one of ordinary skill in the art using only routine experimentation.

The term "HSV glycoprotein" refers to any of the glycoproteins found in the membrane region of HSV-l, HSV-2, and relatsed herpes viruses. Presently preferred HSV glycoproteins are gB, gC, gD, and gE. Included within thiε definition are glycoproteinε extracted from natural viruses (e.g., from infected sera or cell culture) and glycoproteins produce, ^y recombinant methods. Such glycoproteins may be edified, either by chemical or enzymatic means (e.g., by proteolytic cleavage, deglycosylation, etc.), or by mutation, or by recombinant DNA techniques (e.g., by fusing HSV glycoprotein genes with other genes to provide fusion

proteinε, or by deleting or replacing sections of DNA sequence) .

The practice of the present invention will employ, unless otherwise indicated, conventional techniques of molecular biology, microbiology, biochemistry, and immunology, which are within the skill of the art. Such techniques are explained fully in the literature. See, e.g., Sambrook, Maniatiε, & Fitεch, MOLECULAR CLONING, A LABORATORY MANUAL, Second Edition (1989); DNA CLONING, VOLUMES I and II (D.N. Glover, Ed. 1985); OLIGONUCLEOTIDE SYNTHESIS (M.J. Gait Ed. (1984); NUCLEIC ACID HYBRIDIZATION (B.D. Ha es & S.J. Higgins eds. 1984) ; ANIMAL CELL CULTURE (R.I. Freshney ed. 1986) ; IMMOBILIZED CELLS AND ENZYMES (IRL Preεε, 1986; B. Perbal, A PRACTICAL GUIDE TO MOLECULAR CLONING (1984) ; the series, METHODS IN ENZYMOLOGY (Academic Press, Inc.), and particularly Vol. 154 and Vol. 155 (Wu and Grosεman, and Wu, eds., respectively); GENE TRANSFER VECTORS FOR MAMMALIAN CELLS (J.H. Miller and M.P. Calos eds. 1987, Cold Spring Harbor Laboratory) , IMMUNOCHEMICAL METHODS IN CELL AND MOLECULAR BIOLOGY (Academic Press, London), Scopes, (1987); PROTEIN PURIFICATION: PRINCIPLES AND PRACTICE, Second Edition (Springer-Verlag, N.Y.) , and HANDBOOK OF EXPERIMENTAL .IMMUNOLOGY, Volumes I-IV, (D.M. Weir and C.C. Blackwell, eds., 1986.) All patents, patent applications, and publications mentioned herein, both supra and infra, are hereby incorporated herein by reference.

Compositions of the invention, which are used to treat individuals for HSV infection, are comprised of a polypeptide which contains one or more immunogenic epitopes of HSV VP16. The surprising result that HSV VP16 is immunogenic, and protective, is demonstrated in

Examples 4 and 5, infra. Thus, the compositions comprised of polypeptides containing at least one immunogenic epitope of HSV VP16, may be used for treatment of individuals to prevent or lessen the disease symptoms associated with HSV infections. Moreover, the results also show that the addition of an HSV glycoprotein to the vaccine which is comprised of HSV VP16 enhances both the immunogenic and protective effect. Therefore, in a preferred mode, the vaccines are further comprised of at least one immunogenic epitope of an HSV glycoprotein. The glycoprotein epitope may exist on the same polypeptide aε the VP16 epitope, or may exist on a second polypeptide. In a more preferred mode, the glycoprotein,epitope is from HSV gB or HSV gD.

In order to prepare the vaccine, a polypeptide comprised of one or more immunogenic epitopes of HSV VPl€ is provided. If an immunogenic epitope of an HSV glycoprotein is alεo desired in the vaccine it may also be included in the polypeptide comprised of the HSV VP16 epitope, or alternatively, it may be provided m a second polypeptide.

The provided polypeptides may be full-length HSV VP16 and/or HSV glycoproteins. If the provided polypeptides are full length, they may be isolated from the virus. Iεolation and further purification may be accomplished by techniques known in the art. See, for example, Methods in Enzymology, and Scopes, PROTEIN PURIFICATION, which discuss a variety of methods for purifying proteins.

Alternatively, the full length polypeptides may be syntheεized uεing recombinant DNA tecnniques and either the known εequenceε which encode the glycoproteins and the HSV-1 VP16, or the sequence for HSV-2 V?16

provided herein. The full length polypeptides may contain one or more substitutions in the amino acid sequence, as long as the immunogenicity of the designated polypeptide is still evident.

The invention also contemplates the use of polypeptides comprised of truncated HSV VP16 and/or glycoprotein amino acid sequences. The size of polypeptides comprising the truncated HSV VP16 sequences or glycoprotein sequenceε can vary widely, the minimum .εize being a sequence of sufficient size to provide the desired immunogenic epitope, while maximum εize is not critical. For convenience, the maximum εize uεually is not substantially greater than that required to provide the desired epitopes and function(s) of the heterologous sequence, if any. Typically, the truncated HSV amino acid sequence will range from about 5 to about 400 amino acids in length. More typically, however, the viral sequence containing the immunogenic epitope will be a maximum of about 100 amino acids in length, preferably a maximum of about 50 amino acids.

Truncated HSV VP16 or HSV glycoprotein amino acid sequenceε which are immunogenic can be identified in a number of ways. For example, the entire viral protein sequence can be screened by preparing a series of short peptides that together span the entire protein sequence. By starting with, for example, lOOmer polypeptides, it would be routine to test each polypeptide for the presence of epitope(s) showing a desired reactivity, and then testing progressively smaller and overlapping fragments from an identified lOOmer to map the epitope of interest. Screening such peptides in an immunoassay is within the skill of the art, and appropriate immunoasεays for immunogenicity are described in the Exampleε.

Methods of computer analysis of a protein sequence to identify potential epitopes are also known. For example, putative epitopes of HSV-2 VP16 have been determined from the putative amino acid sequence shown in Fig. 2, using as criteria the surface probability, antigen index, hydrophilicity, charge, or lack of overt structure of the regions of the HSV-2 VP16 polypeptide. These putative epitopes are located at about amino acid (aa) 15 to about aa 34; at about aa 193 to about aa 220; at about aa 320 to about aa 330; at about aa 360 to about aa _. 371; at about aa 378 to about aa 390; at about aa 400 to about aa 410; and at about aa 480 to about aa 490.. After tne identification of putative epitopes, oligopeptides comprising the identified regions can be prepared for screening.

If desired, a single polypeptide may include at least one truncated HSV VP16 sequence which includes an immunogenic epitope, and also, at least one truncated HSV glycoprotein sequence which includes an immunogenic epitope. Alternatively, the truncated HSV VP16 and HSV glycoprotein sequences may be on separate polypeptides. While truncated sequences can be produced by various known treatments of the subject native viral protein(s; , it is generally preferred to make synthetic or recombinant polypeptides comprised of the desired immunogenic epitopes.

Recombinant polypeptides. comprised of the truncated HSV VP16 sequences can !_•_ _ade up entirely of VP16 sequences (one or more epitopes, either contiguous or noncontiguous) , or VP16 sequence or sequences in a fusion protein. Similarly, polypeptides comprised of truncated HSV glycoprotein sequenceε can be made up entirely of the glycoprotein sequence (one or more

epitopes, either contiguous or noncontiguous) , or the glycoprotein sequence or sequences in a fusion protein.

In fusion proteins, useful heterologouε sequences include sequences that provide for secretion from a recombinant host, enhance the immunological reactivity of the VP16 or glycoprotein epitope(s), or facilitate the coupling -of the polypeptide to a support or a vaccine carrier. See, e.g., EPO Pub. No. 116,201; U.S. Pat. No. 4,722840; EPO Pub. No. 259,149; U.S. Pat. No. 4,629,783, the discloεureε of which are incorporated herein by reference.

Full length as well as polypeptides comprised of truncated HSV VP16 and/or HSV glycoprotein sequences, and mutants thereof, may be prepared by recombinant technology. A DNA sequence putatively encoding HSV-l VP16 (also known aε VmW65) is discloεed in Campbell et al (1984) , the diεclosure of which is incorporated herein by reference. A DNA sequence encoding HSV-2 VP16, discovered by the herein inventors and described in Example l _y is provided in Fig. 3, infra. In the figure, the Met indicated by the arrow is tne putative initiating methionine. The method for the provision of the sequence of HSV-2 VP16 is simply of historical interest, since the information in the sequence data iε available both in Fig. 3 and in ATCC Deposit No. 68,372, which iε incorporated herein by reference. The sequenceε encoding a number of HSV glycoproteinε, including gB and gD are known. For example, εequences encoding HSV-l and HSV-2 gB are shown in U.S. Patent No. 4,642,333; sequences encoding HSV gD are described in Watson et al. (1982) . Methods for expressing gB and gD, and fragments thereof, are described in WO88/02634. The availability of these

sequences permits the construction of polynucleotides encoding immunogenic regions of the HSV VP16 polypeptides and HSV glycoproteins.

Polynucleotides encoding the desired polypeptide comprised of one or more of the immunogenic HSV VP16 epitopes and/or one or more of the immunogenic glycoprotein epitopes may be chemically syntheεized or isolated, and inserted into an expression vector. The vectors may or may not contain portions of fusion sequenceε such as beta-Galactosidaεe or εuperoxide dismutaεe (SOD) . Methods and vectors which are useful for the production of polypeptides which contain fusion sequences of SOD are described in European Patent Office Publication number 0196056, published October 1, 1986.

The DNA encoding the desired polypeptide, whether in fused or mature form and whether or not containing a signal sequence to permit secretion, may be ligated into expression vectors suitable for any convenient host. The hosts are then transformed with the expression vector. Both eukaryotic and prokaryotic host systems are presently used in forming recombinant polypeptides, and a summary of εome of the more common control systems jend host cell lines is presented infra. The hoεt cells are incubated under conditions which allow expreεεion of the desired polypeptide. The polypeptide is then isolated from lysed cells or from the culture medium and purified to the extent r. --ied for its intended use.

The general techniques used in extracting the genome from a virus, preparing and probing DNA libraries, sequencing clones, constructing expression vectors, transforming cells, performing immunological assays such as radioimmunoassays and ELISA assays, for growing ceils

in culture, and the like, are known in the art and laboratory manualε are available describing these techniques. However, as a general guide, the following sets forth some sources currently available for such procedures, and for materials useful in carrying them out.

Synthetic oligonucleotides may be prepared using an automated oligonucleotide synthesizer as described by Warner (1984) . If desired, the synthetic strandε may be labeled with ^J P by treatment .with ^• " polynucleotide kinase in the presence of 32P-ATP, using standard conditions for the reaction.

In order to create mutants, or to create desired functional sequenceε or to remove them, (e.g., restriction enzyme sites) DNA sequenceε, including those iεolated from cloneε, may be modified by known techniques, including for example, site directed mutagenesiε, aε deεcribed by Zoller (1982) . Briefly, the

DNA to be modified iε packaged into phage as a single stranded sequence, and converted to a double stranded DNA with DNA polymerase using, as a primer, a synthetic oligonucleotide complementary to the portion of the DNA to be modified, and having the deεired modification included in itε own εequence. The reεulting double stranded DNA iε tranεformed into a phage εupporting host bacterium. Cultures of the transformed bacteria, which contain replications of each strand of the page, are plated in agar to obtain plaques. Theoretically, 50% of the new plaques contain phage having the mutated sequence, and the remaining 50% have the original sequence. Replicates of the plaques are hybridized to labeled synthetic probe at temperatures and conditions which permit hybridization with the correct strand, but

not with the unmodified sequence. The sequences which have been identified by hybridization are recovered and cloned.

Generally, in hybridization analysis, the DNA to be probed iε immobilized on nitrocellulose filters, denatured, and prehybridized with a buffer containing 0- 50% formamide, 0.75 M NaCl, 75 mM Na citrate, 0.02% (wt/v) each of bovine serum albumin, polyvinyl pyrollidone, and Ficoll, 50 mM Na phosphate (pH 6.5) , 0.1% SDS, and 100 μg/ml carrier denatured DNA. The percentage of formamide in the buffer, aε well as the time and temperature conditions of the prehybridization and subεequent hybridization εtepε and wash depends on the stringency required. Oligomeric probes which require lower stringency conditions are generally used with low percentageε of formamide, lower temperatures, and longer hybridization times. Probes containing more than 30 or 40 nucleotides such as those derived from cloned DNAs generally employ higher temperatures, e.g., about 40- 42 ^{^} C, and a high percentage, e.g., 50% formamide. Following prehybridization, labeled probe is added to the buffer, and the filterε are incubated in thiε mixture under hybridizaiAon conditionε. After waεhing, the treated filters are subjected to autoradiography to show the location of the hybridized probe; DNA in corresponding locations on the original agar plates iε used as the source of the desired DNA.

Vector construction employε techniqueε which are known in the art. Site-specific DNA cleavage iε performed by treating with εuitable reεtriction enzymes under conditions which generally are specified by the manufacturer of these commercially available enzymeε. In general, about 1 μg of plaεmid or DNA εequence is cleaved

by 1 unit of enzyme in about 20 μl buffer solution by incubation of 1-2 hr at 37 C. After incubation with the restriction enzyme, protein is removed by extraction (e.g., with phenol/chloroform), and the DNA recovered (e.g., by precipitation with ethanol) . The cleaved fragments may be separated, e.g., using gel electrophoresiε techniques or by sedimentation, according to the general procedures found in Methods in Enzymology (1980) 65:499-560.

Sticky ended cleavage fragments may be blunt ended using E. coli DNA polymerase I (Klenow) in the presence of the appropriate deoxynucleotide triphosphates (dNTPs) present in the mixture. Treatment with a εingle stranded nuclease (e.g. , SI nuclease) may also be used to hydrolyze any single stranded DNA portions.

Ligations may be carried out using standard buffer and temperature conditions using T4DNA ligase and ATP. When vector fragments are used as part of a ligation mixture, the vector fragment is often treated with bacterial alkaline phosphatase (BAP) or calf intestinal alkaline phosphatase to remove the 5'- phoεphate and thuε prevent religation of the vector; alternatively, reεtriction enzyme digeεtion of unwanted fragmentε can be used to prevent ligation.

Ligation mixtures are used to transform suitable cloning hosts which are known in the art, e.g., __• coli. and successful transformants are selected by an appropriate marker, for example, antibiotic resistance, and screened for the correct construction.

In order to verify constructions, ligation mixtures are transformed into a suitable hoεt, e.g., E. coli HB101, and εucceεsful tranεfor antε εelected by antibiotic resistance or other markers. Plasmids from

the transformants are then prepared according to the method of Clewell et al. (1969) , usually following chloramphenicol amplification (Clewell (1972)) . The DNA is isolated and analyzed, usually by restriction enzyme analysis and/or sequencing. Sequencing may be by the dideoxy method of Sanger et al. (1977) , as further described by Mesεing et al. (1981) , or by the method of Maxam et al. (1980) . Problemε with band compreεεion, which are sometimes observed in GC rich regions, may be overcome by use of T-deazoguanosine according to Barr et al. (1986) .

Transformation of the vector containing the desired sequence into the appropriate host may be by any known method ^* for introducing polynucleotides into a host cell, including, for example, packaging the polynucleotide in a virus and transducing the noεt ceil with the virus, or by direct uptake of the polynucleotide. The transformation procedure used depends upon the host to be transformed. For example, i vivo transformation using vaccinia virus as the transforming agent for polynucleotideε encoding HSV-2 VP16 is described infra., in the Examples. Transformation may alεo be accompliεhed in vitro εyεtemε. Bacterial transformation by direct uptake generally employε treatment with calcium or rubidium chloride (Cohen (1972); Sambrook (1989)) . Yeast transformation by direct uptake may be carried out . ^* ing the method of Hinnen et al. (1978) . Mammalian _.- . nsformationε by direct uptake may be conducted using the calcium phosphate precipitation method of Graham and Van der Eb (1978) , or the various known modifications thereof. Other methods for the introduction of recombinant polynucleotides into cells, particularly into mammalian

cellε, which are known in the art include dextran mediated transfection, calcium phosphate mediated transfection, polybrene mediated transfection, protoplast fusion, electroporation, encapsulation of the polynucleotide(s) in liposomes, and direct microinjection of the polynucleotides into nuclei.

In order to obtain expreεsion of desired coding sequences, host cells are transformed with polynucleotides (which may be expression vectors) , which are compriεed of control εequenceε operably linked to the deεired coding sequenceε. The control εequences are compatible with the designated host. Among prokaryotic hosts, E. coli is moεt frequently uεed. Expression control sequences for prokaryotes include pro oterε, optionally containing operator portions, and riboεo e binding εiteε. Tranεfer vectors compatible with prokaryotic hpεtε are commonly derived from, for example, pBR322, a plaεmid containing operons conferring ampicillin and tetracycline resiεtance, and the various pUC vectors, which also contain sequences conferring antibiotic reεiεtance markers. Promoter sequences may be naturally occurring, for example, the β-lactamase (penicillinase) (Weissman (1981)) , lactoεe (lac) (Chang et al. (1977) , and tryptophan (trp) (Goeddel et al. (1980)) , and lambda-derived P _L promoter εystem and N gene riboεome binding site .(Shimatake et al. (1981)) . In addition, synthetic promoterε which do not occur in nature alεo function as bacterial promoterε. For example, transcription activation sequenceε of one promoter may be joined with the operon εequences of another promoter, creating a synthetic hybrid promoter (e.g., the tac promoter, which is derived from sequenceε of the trp and lac promoters (De Boer et al. (1983)) . The foregoing

systems are particularly compatible with E. coli,- if desired, other prokaryotic hosts such as strains of Bacillus or Pseudomonas may be used, with corresponding control sequences.

Eukaryotic hosts include yeast and mammalian cells in culture systems. Saccharomyces cerevisiae and Saccharomvces carlsbergensis are the most commonly used yeast hosts, and are convenient fungal hostε. Yeast compatible vectors carry markers which permit selection of successful transformants by conferring prototrophv to auxotrophic mutants or resistance to heavy metals on wild-type strains. Yeast compatible vectors may employ the 2 micron origin of replication (Broach et al. (1983)) , the combination of CEN3 and ARS1 or other means for assuring replication, such as sequences which will result in incorporation of an appropriate fragment intc the host cell genome. Control sequences for yeast vectors are known in the art and include promoterε for the synthesiε of glycolytic enzymeε (Heεε et al. (1968)) ; for example, alcohol dehydrogenase (ADH) (E.P.O. Publication No. 284044) , enolase, glucokmase, glucose- 6-phoεphate iεomeraεe, glyceraldehyde-3-phoεphate dehydrogenase (GAP or GAPDH) , hexokinase, phosphofructokinase, 3-glycerophosphate mutaεe, and pyruvate kinase (PyK) (E.P.O. Publication No. 329203). The yeast PH05 gene, encoding acid phosphatase, also provides useful promoter sequenceε "' yanohara et al. (1983) . In addition, synthetic pror.-Lers which do not occur in nature also function as yeast promoters. For example, upstream activating sequences (UAS) of one yeast promoter may be joined with the transcription activation region of another yeast promoter, creating a synthetic hybrid promoter. Examples of such hybrid promoters

include the ADH regulatory sequence linked to the GAP transcription activation region (U.S. Patent No.ε 4,876,197 and 4,880,734). Other examples of hybrid promoters include promoters which consist of the regulatory sequences of either the ADH2, GAL4, GAL10, or PH05 genes, combined with the transcriptional activation region of a glycolytic enzyme gene such as GAP or PyK (E.P.O. Publication No. 164556) . Furthermore, a yeast promoter can include naturally occurring promoters of non-yeast origin that have the ability to bind yeast RNA polymerase for the appropriate inititiation of transcription.

Other control elements which may be included in the yeast- expression vector are terminators (e.g., from GAPDH, and from the enolaεe gene (Holland (1981)) , and leader sequenceε. The leader sequence fragment typically encodes a signal peptide comprised of hydrophobic amino acids which direct the secretion of the protein from the cell. DNA encoding suitable signal sequences can be derived from genes for secreted yeast proteins, such as the yeast invertase gene (E.P.O. Publication No. 12,873) and the α-factor gene (U.S. Patent No. 4,588,684) . Alternatively, leaderε of non-yeaεt origin, such aε an interferon leader, also provide for εecretion in yeaεt (E.P.O. Publication No. 60057) . A preferred claεε of secretion leaders are those that employ a fragment of the yeast α-factor gene, which contains both a "pre" signal sequence, and a "pro" region. The types of α-factor fragments that can be employed include the full-length pre-pro α-factor leader, as well aε truncated α-factor leaders (U.S. Patent Noε. 4,546,083 and 4,870,008; E.P.O. Publication No. 324274. Additional leaderε employing an α-factor leader fragment that provides for secretion

include hybrid α-factor leaders made with a pre-sequence of a first yeast, but a pro- region from a second yeast α-factor. (See, e.g., P.C.T. WO 89/02463).

Expression vectors, either extrachromosomal replicons or integrating vectors, have been developed for transformation into many yeasts. For example, expresεion vectors have been developed for Candida albicans (Kurtz et al. (1986) ) , Candida maltosa (Kunze et al. (1985) ) , Hanzenula polvmorpha (Gleeson et al. (1986)) , Kluvveromvces fragilis (Das et al. (1984) ) , Kluvveromvces lactis (De Louvencourt et al. (1983)) , Pichia guillerimondii , (Kunze et al. (1985)) , Pichia paεtor s (Cregg et al. (1985); U.S. Patent Noε. 4,837,148 and 4 , 929 , 555) ) , . Schizoεaccharomyceε pombe (Beach and Nurse (1981) ) , and Yarrowia lipolytica (Davidow et al. (1985j ,, .

Mammalian cell lines available as hosts for expression are known in the art and include many immortalized cell lines available from the American Type Culture Collection (ATCC) , including, for example, HeLa cells, Chinese hamster ovary (CHO) cells, baby hamster kidney (BHK) cells, COS monkey cells, and a number of other cell lines. Suitable promoters for mammalian cells are also known in*-the art and include viral promoters such as that from Simian Virus 40 (SV40) , Rous εarcoma viruε (RSV) , adenoviruε (ADV) and bovine papilloma virus (BPV) (See, Sambrook (1989) for examples of suitable promoters) . Mammalian cells may also require terminator sequences and poly A addition sequenceε; enhancer sequences which increase expression may also be included, and sequences which cause amplification of the gene may also be desirable. These sequences are known in the art.

Vectors suitable for replication in mammalian cells are known in the art, and may include viral

replicons, or sequences which ensure integration of the appropriate sequences encoding the desired polypeptides into the host genome.

A vector which is used to express foreign DNA and which may be used in vaccine preparation iε Vaccinia virus. In this case, the heterologous DNA is inserted into the Vaccinia genome. Techniques for the insertion of foreign DNA into the vaccinia viruε genome are known in the art, and utilize, for example, homologouε recombination. The inεertion of the heterologouε DNA is generally into a gene which is non-esεential in nature, for example, the thymidine kinaεe gene (tk) , which also provides a εelectable marker. Plasmid vectors that greatly facilitate the construction of recombinant viruses have been described (see, for example, Mackett et al. (1984) , Chakrabarti et al. (1985) ; Moss (1987)) . Expreεεion of the desired polypeptides compriεed of immunogenic regions then occurε in cells or individuals which are infected and/or immunized with the live recombinant vaccinia viruε.

Other syεtems for expreεsion of polypeptides include insect cells and vectors εuitable for use in these cells.. These εystemε are known in the art, and include, for example, inεect expression transfer vectors derived from the baculoviruε Autographa californica nuclear polyhedrosis virus (AcNPV) , which is a helper- independent, viral expression vector. Expreεsion vectors derived from this system usually use the strong viral polyhedrin gene promoter to drive expression of heterologous genes. Currently the most commonly used tranεfer vector for introducing foreign geneε into AcNPV iε pAc373, εhown in Fig.- 4. Many other vectors, known to those of skill in the art, have also been designed for

improved expression. These include, for example, pVL985 (which alters the polyhedrin start codon from ATG to ATT, and which introduces a BamHI cloning site 32 basepairs downstream from the ATT; See Luckow and Summers (1989) . AcNPV transfer vectors for high level expression of nonfused foreign proteins are shown in Fig. 4. In the figure, the numbers shown refer to positions within the native gene, where the A of the ATG codon is +1. Fig. 4 also shows a restriction endonuclease map of the transfer vector pAc373. The map showε that a unique BamHI site is located following position -8 with respect to the tranεlation initiation codon ATG of the polyhedrin gene. There are no cleavage sites for Smal, PstI, Bgll, Xbal or Sstl. Good expression of nonfused foreign proteins usually requires foreign genes that ideally have a short leader sequence containing suitable translation initiation εignalε preceding an ATG start signal. The plasmid alεo containε the polyhedrin polyadenylation signal and the ampicillin-resistance (amp) gene and origin of replication for selection and propagation in E. coli.

Methods for the introduction of heterologous DNA into the deεired site in the baculovirus are known in the art. (See Summerε and Smith, Texaε Agricultural Experiment Station Bulletin No. 1555; Ju et al. (1987) ; Smith et al. (1983); and Luckow and Summers (1989)) . For example, the insertion can be into . gene such as the polyhedrin gene, by homologous reccr-ination; insertion can also be into a restriction enzyme site engineered into the desired baculovirus gene. The inserted sequenceε may be thoεe which encode all or varying segmentε of HSV VP16 and/or HSV glycoprotein.

The signals for posttranslational modifications, such as signal peptide cleavage, proteolytic cleavage, and phosphorylation, appear to be recognized by insect cells. The signals required for secretion and nuclear accumulation alεo appear to be conserved between the invertebrate and vertebrate cells. Examples of the signal sequences from vertebrate cells which are effective in invertebrate cells are known in the art, for example, the human interleukin 2 signal (IL2 ) which is a εignal for tranεport out if the cell, is recognized and properly removed in -insect cells.

It iε often desirable that the polypeptides prepared using the above host cells and vectors be fuεion polypeptideε. Aε with non-fusion polypeptides, fusion polypeptides may remain intracellular after expresεion. Alternatively, fuεion proteinε can alεo be secreted from the cell int© the growth medium if they are comprised of a leader sequence fragment. Preferably, there are processing sites between the leader fragment and the remainder of the foreign gene that can be cleaved either in vivo or in vitro.

In instances wherein the synthesized polypeptide is correctly configured εo aε to provide the correct epitope, but iε too small to be immunogenic, the polypeptide may be linked to a suitable carrier. A number of techniques for obtaining such linkage are known in the art, including the formation of disulfide linkages using N-εuccinimidyl-3-(2-pyridyl-thio)propionate (SPDP) and succinimidyl 4-(N-maleimidomethyl) cyclohexane-1- carboxylate (SMCC) (if the peptide lacks a sulfhydryl group, thiε can be provided by addition of a cyεteme residue.) These reagents create a disulfide linkage between themselveε and peptide cyεteine reεides on one

protein and an amide linkage through the e-amino on a lysine, or other free amino group in other amino acids. A variety of such disulfide/amide-forming agents are known. See, for example, Immun. Rev. (1982) 62 : 185. Other bifunctional coupling agents for a thioether rather than a disulfide linkage. Many of these thio-ether- for ing agents are commercially available and include reactive esters of 6-maleimidocaproic acid, 2-

10 bromoacetic acid, 2-iodoacetic acid, 4-(N-maleimido- methyl) cyclohexane-l-carboxylic acid, and the. like. The carboxyl groupε can be activated by combining them with εuccinimide or l-hydroxyl-2-nitro-4-εulfonic acid, εodium salt. Additional methods of coupling antigens employ the

15 rotaviruε/"binding peptide" syεtem described in EPO Publication No. 259,149. The foregoing liεt is not meant to be exhaustive, and modifications of the named compounds can clearly be uεed.

Any carrier may be uεed which doeε not itself

20 induce the production of antibodies harmful to the host. Suitable carriers are typically large, slowly metabolized macromoleculeε such as proteins; polysaccharides such aε latex functionalized sepharose, agarose, cellulose, cellulose beads j d the like; polymeric amino acids, such m m as polyglutamic acid, polylyεine, and the like; amino acid copolymers; and inactive virus particles (see infra.) . Especially useful protein substrates are serum albumins, keyhole limpet hemocyanir immunoglobulin molecules, thyroglobulin, ovalbumin .etanus toxoid, and

30 other proteins well known to those of skill in the art.

The immunogenicity of the epitopes of HSV VP16, particularly of HSV-2 VP16, and of HSV glycoproteins, particularly HSV gB and/or HSV gD, may also be enhanced by preparing them in eukaryotic systems fused with or

assembled with particle-forming proteinε such aε, for example, that associated with hepatitis B surface antigen. See, e.g., U.S. Patent No. 4,722,840. Constructs wherein the HSV VP16 or glycoprotein epitope is linked directly to the particle-forming protein coding sequences produces hybrids which are immunogenic with respect to the HSV epitope. In addition, all of the vectors prepared include epitopes specific to HBV, having various degrees of immunogenicity, such aε, for example, the pre-S peptide. Thuε, particleε conεtructed from particle forming protein which include HSV εequenceε are immunogenic with reεpect to HSV and HBV.

Hepatitis surface antigen (HBSAg) has been εhown to be formed and asεembled into particleε in S_. cerevisiae (Valenzuela et al. (1982) , aε well as in, for example, mammalian cellε (Valenzuela et al . (1984)) . The formation of εuch particleε haε been εhown to enhance the immunogenicity of the monomer εubunit. The constructs may alεo include the immunodominant epitope of HBSAg, compriεing the 55 amino acidε of the preεurface (pre-S) region. Neurath et al. (1984) . Conεtructε of the pre- S-HBSAg particle expressible in yeast are discloεed in E.P.O. Publication No. 174,444; hybridε including heterologouε viral εequenceε for yeast expresεion are discloεed in E.P.O. Publication No. 175,261. These conεtructs may also be expreεsed in mammalian cells such as CHO cells using an SV40-dihydrofolate reductase vector (Michelle et al. (1984)).

In addition, portions of the particle-forming protein coding εequence may be replaced with codonε encoding an HSV VP16 or HSV glycoprotein epitope. In thiε replacement, regionε which are not required to mediate the aggregation of the unitε to form immunogenic

particles in yeast or mammals can be deleted, thus eliminating additional HBV antigenic sites from competition with the HSV epitope(s).

The preparation of vaccines which contain an immunogenic polypeptide(s) as an active ingredient(s) iε known ^" to one skilled in the art. Typically, such vaccines are prepared aε injectableε, either aε liquid εolutions or suspensionε; solid forms suitable for solution in, or suspension in, liquid prior to injection may also be prepared, the preparation may alεo be emulεified, or the polypeptide(s) encapsulated in liposomes. The active immunogenic ingredients are often mixed with excipients which are pharmaceutically acceptable and compatible with the active ingredient. Suitable excipientε are, for example, water, saline, dextroεe, glycerol, ethanol, or the like and combinationε thereof. In addition, if deεired, the vaccine may contain minor amountε of auxiliary substanceε εucn as wetting or emulsifying agents, pH buffering agents, and/or adjuvants which enhance the effectiveness of the vaccine. Examples of adjuvants which may be effective include, but are not limited to: aluminum hydroxide, N- acetyl-muramyl-L*threonyl-D-iεoglutamine (thr-MDP) , N- acetyl-nor-muramyl-L-alanyl-D-isoglutamine (CGP 11637j , referred to aε nor-MDP) , N-acetylmuramyl-L-alanyl-D- isoglutaminyl-L-alanine-2-(1'-2 '-dipalmitoyl-sn-glycero- 3-hydroxyphosphoryloxy)-ethylamine (CGP 19835A, referred to as MTP-PE, and RIBI, which contains three components extracted from bacteria, monophosphoryl lipid A, trehalose dimycolate and cell wall skeleton (MPL+TDM+CWS) in a 2% squalene/Tween 80 emulεion. The effectiveneεε of an adjuvant may be determined by meaεuring the amount of antibodieε directed against an immunogenic polypeptide

containing an HSV-VP16 epitope and/or HSV glycoprotein epitope, the antibodies resulting from administration of this polypeptide in vaccines which are also comprised of the various adjuvants.

The proteins may be formulated into the vaccine as neutral or salt forms. Pharmaceutically acceptable salts include the acid addition saltε (formed with free amino groups of the peptide) and which are formed with

10 inorganic acids such aε, for example, hydrochloric or phosphoric acids, or organic acids εuch aε acetic, oxalic, tartaric, maleic, and the like. Salts formed with the free carboxyl groups may also be derived from inorganic bases such as, for example, sodium potasεium,

15 ammonium, calcium, or ferric hydroxideε, and εuch organic bases as isopropylamine, trimethylamine, 2-ethylamino ethanol, histidine, procaine, and the like.

The vaccineε are conventionally adminiεtered parenterally, by injection, for example, either

20 subcutaneously or intramuscularly. Additional formulations which are suitable for other modes of administration include suppositories and, in some cases, oral formulations. For suppoεitorieε, traditional binders and carriers may include, for example,

25 polyalkylene glycols or triglycerides;εuch εuppoεitories may be formed from mixtureε containing the active ingredient in the range of 0.5% to 10%, preferably l%- 2%. Oral formulations include such normally employed excipients as, for example, pharmaceutical grades of

30 mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, and the like. These compositions take the form of solutions, εuεpensions, tablets, pills, capsuleε, εuεtained release

_ D

formulations or powders and contain l0%-95% of active ingredient, preferably 25%-70%.

In addition to the above, it is also posεible to prepare live vaccines of attenuated microorganisms which express one or more recombinant polypeptides comprised of HSV VP16 and/or HSV glycoprotein epitopes. Suitable attenuated microorganisms are known in the art and include, for example, viruses (e.g., vaccinia virus)

10 aε well aε bacteria.

The vaccines are administered in a manner compatible with the dosage formulation, and in such amount aε will be prophylactically and/or therapeutically effective. The quantity to be adminiεtered, which iε generally in ^* the range of 5 μg to 250 μg of antigen per doεe, dependε. on the εubject to be treated, capacity of the subject;s immune system to synthesize antibodies, and the degree of protection desired. Precise amountε of active ingredient required to be adminiεtered may depend

20 on the judgment of the practitioner and may be peculiar to each individual.

The vaccine may be given in a εingle doεe schedule, or preferably in a multiple dose schedule. A multiple doεe εchedule iε one in which a primary courεe

25 of vaccination may be with 1-10 separate doseε, followed by other doses given at subsequent time intervals required to maintain and/or reenforce the immune response, for example, at 1-4 mon ^t s for a second dose, and if needed, a subsequent dose(.~ after several months.

30 The dosage regimen will also, at lest in part, be determined by the need of the individual and be dependent upon the judgment of the practitioner.

In addition, the vaccine containing tne polypeptide comprised of an immunogenic HSV VP16 epitope

_ D

may be administered in conjunction with other immunoregulatory agents, for example, immune globulins.

Examples Example 1 Isolation and Sequencing of a Gene Encoding HSV-2 VP16 The EcoRI "L" fragment of HSV-2 εtrain G waε inserted into pUC19 to yield pH2G512, the source of the 0 polynucleotide which encodeε HSV-2 VP16. The HSV-2 polynucleotide encoding εequence waε identified by • Southern blot analysis, using aε probe a εegment of pRB3458, which containε the sequence which encodes HSV-l VP16. The plasmids pH2G512 and pRB3458 were obtained from Dr. P. Pellett (Center for Disease Control, Atlanta, Ga.) and Dr. B. Roizman (University of Chicago, Chicago, 111.), respectively. The construction of pRB3458 is described in "Pellet et al. (1985) .

More specifically, the HSV-2 VP16 encoding 0 polynucleotide, pH2G512 was digested with EcoRI, and EcoRI and Sad, SacII, BamHI, Ncol, and Smal, respectively. The fragmentε of the digeεted plaεmid were εeparated by electrophoresis on a 1% agarose gel in triε- acetate buffer. After electrophoresis, the DNA in the m gel was denatured with alkali, neutralized, and transferred to a "Gene Screen Pluε" membrane (Dupont NEN) , using the transfer protocol described in Sambrook et al. (1989) . The DNA on the membrane was hybridized with the probe overnight using the manufacturer's directionε; the probe waε a nick-tranεlated 2.9 Kb EcoRI- Hindlll fragment iεolated from pRB3458. Reεults of the hybridization εhowed that HSV-2 VP16 iε encoded in a 3.5Kb EcoRI-SacI fragment of pH2G512. Subεequently, tne VP16 encoding EcoRI-SacI fragment waε iεolated on a 1% 5

agarose gel, and extracted from the gel using "Gene Clean" (Bio 101) . Sequencing of the fragment waε accomplished by the dideoxy method. Since HSV DNA is G- C rich (i.e., >70% G-C) , sequences in areas of compressions in the sequencing gels were resolved by sequencing with Taq polymerase at 65°C. The sequence of the coding strand of the fragment, and the amino acids encoded therein, are shown in Fig. 3. In the figure, the first nucleotide of the putative initiating methionine codon is εhown by an arrow.

Homologieε between the putative amino acid sequences for HSV-l VP16 and HSV-2 VP16 are shown in Fig. 2. Example 2

Construction of a Vaccinia Virus Expression Vector Comprised of a Sequence Encoding HSV-2 VP16

A vaccinia vector comprised of a sequence encoding HSV-2 VP16 was constructed aε follows. Initially the VP16 encoding sequence waε εubcloned intc the vaccinia expression vector, pSCll, to generate plasmid pHS225 (a partial map of which iε εhown in Fig. 5. The vector pSCll waε obtained from Dr. Bernard Moεε, National Inεtitufceε of Health, Betheεda, Maryland. Prior to introduction of the HSV-2 VP16 coding εequence, the pSCll vector waε modified by deletion of the Hindlll site in pSCll by digestion with Hindlll, followed by treatment with the Klenow fragment of DNA po_ - .rase I, and ligation. The vector was then furtn__ modified by the introducing into the Smal site, a polylinker containing restriction enzyme sites for Smal, Kpnl, Bglll, and Hindlll. The fragment containing VP16 waε iεolated as a 2.1 Kb XhoI-SphI fragment from pH2G512. The Xho site was filled in using the Klenow fragment of DNA polymerase I,

and the SphI site was blunted using T4 DNA polymerase. The blunt-ended fragment was then ligated into the Smal site of the modified pSCll. Vectors containing the VP16 encoding sequence were obtained by cloning; they were transformed into DH5α and transformants were selected using Ap ^r selection; positive clones were selected based on the presence of the appropriate εize fragment after restriction enzyme analysis. One of the positive clones was named pHS225. A map showing some of the significant features of pHS225 is shown in Fig. 5.

In order to obtain a recombinant vaccinia viruε vector which was suitable for expressing VP16 in individuals, the VP16 encoding sequence of pHS225 was inserted into the TK locus of wild type vaccinia strain, WR, by recombination using the Lipofectin transfection protocol described by the manufacturer of Lipofectin (BRL Laboratories) ." Recombinant TK ^~ viruses were isolated by BuDR selection, and plaque-purified using the protocol of Mackett et al. (1987) . A vaccinia/VP16 recombinant clone was selected by DNA dot blot hybridization. Expression of VP16 _. was verified by Western Blot and radioimmunoprecipitation, and the recombinant clone waε subsequently purified. The details of this procedure are as follows.

In order to obtain recombinants of pHS225 with vaccinia WR, confluent monolayerε of BSC40 cells in T-25 flasks were infected with WR at a multiplicity of infection (moi) of .05; adsorption was performed for two hours at room temperature with rocking. Three pHS225 εolutions were prepared with Lipofectin (BRL Laboratories) as follows: 50 μl of a DNA solution containing either 1, 10, or 100 μg pHS225 in water were mixed with 30 μg Lipofectin plus 20 μl water. Tne

solutions were allowed to incubate at room temperature for 15 minutes. The infected cells were washed twice in serum free medium; 3 ml of serum free medium was added to each flask; then 100 μl of a DNA-lipofectin complex was added dropwise to each flask with swirling. Transfections were incubated at 37" in an atmoεphere containing 7% C0 ₂ for 5 hourε. Then 3 mlε of DME containing 20% fetal calf serum (FCS) waε added to each flask (final FCS concentration was 10%) , and the transfections were incubated for 48-72 hours. After the incubation, recombinant virus was harvested by scraping the cells into the medium. Virus was released from the cells by freeze-thawing the cells three times.

Recombinant viruses containing VP16 were selected using the technique of Mackett et al. (1987, . Briefly, the viruε εtock generated by each transfection was thawed, sonicated and incubated 30 min. at 37 ^{^} C in the presence of 0.1 volume of 0.25% trypεin. Monolayers of TK-143 cells were infected with 10-fold serial dilutions of the trypεinized εtock. After adsorption, the cells were overlaid with DME containing 1% low melting point agarose, 5% FCS and 25 μg BUDR (Sigmε Chemical Co.) . _.t 48 hours post infection (p. .) , the cellε were stained with 1% agarose containing 0.1% neutral red. After 3 to 5 hours, viral plaques were visualized as clearings in the cell lawn. Plaques were picked, and subjected to two more rounds of plaque purification using BUDR.

Verification that the selected recombinantε contained the VP16 encoding sequence waε accomplished by dot blot hybridization. The dot blot technique waε essentially according to the technique of Mackett et al. (1987) , except that detection was with a fragment

encoding VP16. Briefly, cellε infected with putative recombinantε were dotted onto nitrocelluloεe uεing a dot blot manifold, lysed and denatured. Filters were baked at 80 C in vacuo for 2 hours, treated before hybridization with a solution containing 60% formamide, 1% sodium dodecyl sulfate (SDS) , 1 M NaCl, 10% dextran sulfate, and hybridized with 10 6 cpm/ml of [32P] labeled VP16. Hybridizations were carried out overnight at 42°C in a solution containing 60% formamide, 1% sodium dodecyl sulfate (SDS) , 1 M NaCl, 10% dextran sulfate, 10 mg/ml salmon sperm DNA, 10 mg/ml poly A~ DNA and 50 mg/ml yeas. tRNA. After hybridization, the filterε were washed four times with 2 x SSC for 5 minutes at room temperature, once with 2 x SSC, 0.1% SDS for 30 minutes at 65°C, and once with 0.1 x SSC, 0.1% SDS for 30 minutes at 65°C. The reεultε of the hybridization showed that 6 Of 12 isolates were positive for the HSV-2 VP16 coding εequence, and that 2 of the 12 iεolates were strongly poεitive. Six iεolateε prepared as described above were chosen for further analysis of the expreεεion of VP16.

Example 3 Expreεsion of VP16 from Recombinant W-VP16 Vectors Expression of VP16 from the W-VP16 clones described in Example 2 waε detected by radioimmunoprecipitation of [ 35S]-labeled infected cell lysateε using high-titer positive human εera followed by SDS-polyacrylamide gel electrophoreεiε of the precipitated productε, and εubsequent visualization of [ 35S]-labeled-VP16 by autoradiography. More εpecifically, the εampleε were electrophoreεed on 8%,

1.5mm thickness polyacrylamide gels (Novex Corp.) for 90 minutes at 40 mA. After electrophoresiε the gels were

fixed, "enhanced" and dried prior to exposure to film. The apparent molecular weight of the recombinant VP16 (Vmw65) is 65 kD. The identity of VP16 was confirmed by radioimmunoprecipitation of protein from HSV-2 infected Vero cells, using the VP16 specific monoclonal antibody, LPl, for the precipitation. LP1, which is described in McLean et al. (1982), was obtained from A. Minεon, Cambridge University. The labeled precipitated product from the W-VP16 infected cellε co-migrated during electrophoreεiε with the labeled precipitated product from the Vero cellε. Thiε co-migration during electrophoreεiε of the VP16 expreεεed in .Vero cellε and from the recombinant vaccinia viruε-VP16 (W-VP16) cellε indicate that the W-VP16 product iε full length.

It is of interest that the antibody LF1 does not recognize VP16 expresεed in the W-VP16 cells, whereas it does recognize VP16 expresεed in HSV infected Vero cellε. It iε poεεible that the change in antibody recognition in the vv-VP16 product reεults from a lack of phosphorylation of the recombinantly produced polypeptide, or other differenceε in protein proceεsing, since vaccinia viruε replicateε in the cytoplasr. of the infected cell.

Example 4 Immunogenicity and Protective Effect of Immunization with ';^.6 or qB2 In order to compare the - ^{• c} ect of immunization with VP16 to that with gB2, with respect to their immunogenicity and protection against HSV-2 cauεed diεeaεe, vaccinia virus recombinants encoding each polypeptide were used to immunize guinea pigε. The vaccinia recombinant uεed which containε the gene codinα

for VP16 was that described in Example 2, i.e., W-VP16 (also called w-VP16-TK~) . The gB recombinant waε prepared by subcloning a polynucleotide encoding gB2 into a pUC13 vector. The gB2 encoding polynucleotide, which was a 3.2 Kb Hindlll - BamHI fragment, contained nucleotides from position -136 _. to 3088, as ^' shown in Fig. 4 in WO88/02634; the latter figure is included herein aε Fig. 6. Significant features of the reεulting vector,

10 pHS218, are shown in Fig. 7. In order to produce a vaccinia virus expresεion vector encoding gB2,- a 3.2. Kb Hindlll - BamHI fragment excised from pHS218 was blunt ended, and ligated into the Hindi site of pCB07 yielding the vector, pVACC-gB2 ^~ . Significant features of the

15 vectors pCB07 and pVACC-gB2 are shown in Fig. 8 and Fig. 9, respectively. Similar to the W-VP16 construct, this places the vaccinia.promoter, 7.5, upstream of the gene; the flanking -thymidine kinaεe (TK) sequences provide for recombination into the wild type viruε at thiε locus. _ ₀ The construction of pVACC-gB2 from pHS218 was performed by Dr. Ian Ramshaw, The John Curtin School of Medical Research, The Australian National University, Canberra, _. Australia. The procedures for the production of the vaccinia expreεεion vector, w-gB2, from wild-type

25 vaccinia viruε were εimilar to thoεe for the production of W-VP16, except that recombination was with pVACC- gB2 , and selection for positive clones was by hybridization with a radiolabeled fragment encoding gB2.

Female guinea pigs were immunized either

30 intradermally (by scarification of the εkin below the right intercostal margin with a bifurcated needle) , interperitoneally, or intravenously (into an ear vein using a 30 gauge needle) .. The protocol for each the groups in the study are shown in the following Table.

Table Immunization with w-gB2 or W-VP16

Group Route of Immunization Immunizations I & II

1 I.D. 10 ⁸ pfu w-gB2 2 I.P. 10 ⁸ pfu w-gB2

3 I.V. 10 ⁸ pfu w-gB2

4 I.D. ιo° pfu w-vpie 5 I.P, 10 ^s pfu w-VPl£ 6 I.V. 10 ⁸ pfu W-VP16

The animals were immunized twice with a one- month interval between immunizations. The animals were bled for the determination of HSV-εpecific and vaccinia- specific neutralizing antibodies at 3 and 6 weeks following the second immunization. Animals in groups 1

₅ through 6 were challenged with 3 x 10 pfu of HSV-2 strain MS; challenge was on day 64, 6 weeks after the second immunization boost. Challenge was by intravaginal inoculation of HSV-2. The animalε were εcored for acute disease the first 14 days post-challenge.

In ordfer to measure the immunogenicity of VP16 and gB2 , the titers of neutralizing antibodies resulting from the immunizations, both complement dependent and complement independent, were determined as follows. A suspension of 150 μl of Vero cellε 1 x 10 cellε per

15 ml medium containing 10% fetal cc. εerum (FCS)) were seeded in two 96 well flat bottom plateε ("Microteεt III"

Tissue Culture plates from Falcon) , and incubated overnight in a CO-, incubator at 37 ^" C. On the next day, samples were prepared in a third 96 well plate, the well contents were aε shown in Fiα. 10. In the figure, the

medium was DME-H21 tissue culture medium, heat- inactivated fetal calf serum (HI FCS) waε prepared by incubating FCS (Hyclone Corp.) at 56"C for 30 min., the guinea pig complement was a 1:125 dilution of rehydrated guinea pig complement (Gibco Corp., prepared according to the manufacturer's directions) . A fourth plate was alεo prepared, which was analogous to the third plate, but in which the guinea pig complement was omitted. The plates were incubated for 2 hours. Viral absorption and replication was accomplished by aspirating the culture medium from the cell monolayers in plateε 1 and 2. The contentε of the correεponding wellε in plateε 3 and 4 were transferred to plates 1 and 2, respectively, and the plates were maintained in a C0 ₂ incubator at 37"C for three days. In order to detect cell cytolysis due to viral replication, after the three day incubation, the culture medium waε aspirated from the cellε, 100 μl of a phosphate buffered saline solution containing 10% formaldehyde εolution and .09% cryεtal violet was added to each well. The plateε were incubated 15 min at room temperature, the crystal violet εolution waε removed, and the wellε were waεhed three timeε with water and the plateε were air dried. The viral titers were 3(2 ⁿ ) and

2(2 ⁿ ) for the complement dependent and complement independent samples, respectively; n equals the serum dilution that inhibits cytolysis of the cell monolayer by 50%.

The reεults on the antibody titrationε, expressed as the mean neutralizing titers found in bleeds 1 and 2 for HSV-specific complement dependent neutralizing antibody titers are shown in Fig. 11. As seen in the figure, at 3 weeks (bleed 1) , I.V. administration of vv-VP16 increased the complement

dependent neutralizing antibodies approximately five¬ fold higher than did w-gB2.

The HSV-specific complement independent neutralizing antibody titers for bleed 1 are shown in the following Table. As seen from the Table, I.V. administration of W-VP16 yielded titers of antibodies which exceeded HSV-specific titers induced by the w-gB2 recombinant by >10 fold. Neutralization waε determined aε 50% reduction in plaque formation. Animalε immunized with wild-type non-recombinant vaccinia, WR, do not elicit measurable neutralizing antibodies.

Table

The effect of immunization with W-VP16 and vv- gB2 on protection as reflected in lesions and the severity of acute disease were also compared. The clinical course of primary genital HSV-2 infection is generally as follows. Lesions first appear on the external genitalia of all animals three to four days after viral inoculation. The lesions begin as discrete veεicleε with an erythematous base, and rapidly progreεε to multiple veεiculo-ulcerative leεionε by dayε 5-8. Hemorrhagic cruεts cover the ulcerative lesionε by dayε 8-10. Loss of the crusts with complete healing cf the

external genital skin occurs by dayε 13-15. Most animalε develop urinary retention between day 5 and day 10; however, this symptom iε resolved by days 10-15. Hindlimb paralysis may be evident in 0% to 20% of animals by days 7-10; this symptom is resolved by days 15-20. Infection and external genital lesions occur in 80-100% of the inoculated animals with death rates of 0-50%. The lesion scoring for the studies waε according to the following scale:

0.5 = redness, swelling;

1.0 = 1-2 veεicleε, or 1 veεicle accompanied by redness and swelling;

1.5 = 2-4 small veεicleε (1-2 mm diameter) or 2 veεicleε accompanied by εwelling and redness;

2.0 = 4-6 vesicles

2.5 = 4-6 large veεicleε (greater than 2 mm diameter) with swelling and redness;

3.0 = greater than 6 large vesicleε;

3.5 = greater than 6 large veεicleε accompanied by additional εmaller vesicleε;

4.0 = confluent veεicleε covering greater than one-half of the perineum;

4.5 = extreme veεicleε with ulceration.

The reεultε comparing the effect of the immunization with W-VP16 to w-gB2 on protection againεt the disease as indicated by the occurrence and severity of leεionε aε well as on mortality, are shown in the following Table. In the study all animals developed lesionε; the leεion εcore for the unimmunized control group was 3.10.

Table

The time course of protection with the different routes of immunization with vv-gB2 and vv-VPl6 are shown in Fig. 12 and Fig. 13, respectively.

Example 5

Immunogenicity and Protective Effect of Immunization with VP16 and gB2

The immunogenicity and protective effect of Ww-' VP16 and w-gB2 against HSV-2 caused disease was examined using a protocol εimilar to that in Example 4, except that the adminiεtration of the vaccines was I.V., and the challenge dose with HSV-2 strain MS was 6 x 10 pfu. The vaccines were administered to four - Dups aε followε: group 1, no treatment; group 2, w-v_- ^' _6 - w-gB2 ; group 3, w-gB2 alone; and group 4, W-VP16 alone.

The reεults of the study on the production of complement-dependent neutralizing antibody titers is shown in the following Table. In the study, neutralization waε determined as 50% reduction m plaque

formation. Animals immunized with vaccinia WR do not elicit measurable neutralizing antibodies (<16) . These results indicate that, at three weeks post-immunization, treatment with vaccine comprised of both W-VP16 and w- gB2 caused higher titers of neutralizing antibodies than did either w-gB2 or W-VP16 alone; at six weeks immunization with W-VP16 appeared to be almost equivalent to that with W-VP16 and w-gB2 with respect to the antibody titers.

Table

Effect of W-VP16 and w-gB2 on Complement Dependent Neutralizing Antibody Titers

The protective effect of the combined vaccine comprised of W-VP16 and vv-gB2 relative to the single subunit vaccines was ^" alεo monitored, using the procedures (with the above modificationε) and scoring described in Example 4. In the study, all of the animalε exhibited lesions. However, the results, shown in the following Table, indicated that the acute disease was ameliorated by the vaccines, and that the protective effect of the combination vaccine waε enhanced relative to either w- gB2 or W-VP16 alone. The time courεe of the protective effect iε shown in Fig. 14.

Table

The following listed materials are on deposit under the terms of the Budapest Treaty with the American Type Culture Collection (ATCC), 12301 Parklawn Dr., Rockville, Maryland 20852, and have been asεigned the following Acceεεion Numberε

Material Depoεit Date ATCC No, pHS226 in E. coli DH5α 15 July 1990 68372

Upon allowance a_nd iεεuance of thiε application as a United States Patent, all restriction on availability of theεe depoεitε will be irrevocably removed; and accesε to the deεignated deposits will be available during pendency of the above-named application to c - determined by the Commiεεioner to be entitled thereto _.der 37 CFR 1.14 and 35 USC 1.22. Moreover, the designated depositε will be maintained for a period of thirty (30) yearε from the date of depoεit, or for five (5) yearε after the last request for the deposit; or for the enforceable life of the U.S. patent, whichever is longer. The deposited

materialε mentioned herein are intended for convenience only, and are not required to practice the present invention in view of the descriptions herein, and in addition these materials are incorporated herein by reference.

Industrial Applicability The compositions described herein, which contain an immunogenic polypeptide comprised of an epitope of HSV VP16, are useful for the alleviation of symptoms resulting from herpes simplex virus infections. The recombinant vectorε, expreεεion systems, and host cellε tranεformed by theεe vectorε are useful for the preparation of the immunogenic polypeptides, which in turn are uεeful in the preparation of the above described vaccines.