Abstract:
A gene of varicella-zoster virus (VZV) which encodes immunogenic outer surface viral proteins has been identified through DNA sequence analysis. Fragments of the DNA have been cloned into a vector which, when placed into a host organism, expresses proteins which react with human convalescent zoster sera and with monoclonal antibodies which neutralize viral infectivity. These proteins are useful for preparation of a vaccine for VZV.

Description:
BACKGROUND OF THE INVENTION 
     Chickenpox is caused by varicella-zoster virus (VZV), a member of the herpesvirus group. The disease occurs in persons with no prior VZV immunity. VZV-specific antibodies can be demonstrated shortly after onset of disease, decline during convalesence, but remain detectable for many years and correlate with immunity to the disease. Chickenpox is highly contagious; over 90% of the population becomes exposed to VZV during the first two decades. The disease is highly morbid to the immunosuppressed and to those beyond the second decade. In most, if not all cases, VZV becomes latent in dorsal root ganglion cells. From this latent state, VZV can reactivate and cause zoster even in the presence of specific antibodies, probably as a result of weakened cellular immunity. 
     VZV has six major glycoproteins on its surface: gp105, gp92, gp83, gp62, gp57, gp55. These glycoproteins apparently are the products of three genes: gA (gp105), gB (gp62, gp57) and gC (gp92, gp83, gp55). The gC glycoproteins are the majority and most immunogenic VZV glycoproteins. Some monoclonal antibodies to gA and gB display complement-independent neutralization, and monoclonal antibodies to gC display complement-dependent neutralization. 
     OBJECTS OF THE INVENTION 
     It is an object of the present invention to provide antigens which will prevent diseases associated with VZV infections. Another object is to provide antigens which can be used diagnostically to measure VZV antibody titers. Another object is to provide methods for the preparation of these antigens. Another object is to provide methods for using the antigens to raise antibodies, both in vivo and in vitro to VZV. Another object is to describe the full sequence of protein antigens which will include peptide antigens which may be synthesized by other means or expressed in other vectors. These and other objects of the present invention will be apparent from the following description. 
     SUMMARY OF THE INVENTION 
     The DNA sequence of the VZV gC gene has been identified. A fragment of the DNA has been cloned into a vector which, when placed in a host organism, expresses proteins which react with convalescent zoster sera and with neutralizing monoclonal antibodies to gC. These proteins are useful for preparation of a vaccine to VZV. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to identification of the VZV DNA which encodes the protective immunogenic glycoproteins gp92, gp83 and gp55. More specifically, it is directed to a 2.0 Kbp DNA fragment and to a 0.9 Kbp DNA fragment whose respective nucleotide sequences and amino acid sequences have been located within the known sequence of the entire VZV genome. 
     The present invention also is directed to vectors containing all or part of these 2.0 and 0.9 Kbp DNA fragments. The invention also is directed to host cells which contain these vectors and which cells are capable of expressing all or part of the peptides encoded by the 2.0 and 0.9 Kbp fragments. In accordance with known techniques, it will be obvious to those skilled in the art that parts of the foregoing peptides could be chemically synthesized or modified and retain their immunogenicity. Therefore, the present invention also is directed toward chemical synthesis of domains of these proteins, especially domains including and surrounding hydrophilic regions and threonine or serine and asparagine-X-serine or asparagine-X-threonine residues (wherein X is any amino acid), since these domains are likely to reside on the outer surface of the virus. 
     RNAs are isolated from cells producing VZV. These RNAs are preselected by hybridization to the HindIII-C, EcoRI-A, or EcoRI-E DNA fragments and translated in vitro. The polypeptide products are immunoprecipitated with monoclonal antibody specific for gC polypeptides. These DNA fragments select RNA which translates to the 70Kd precursor of the gp92, gp83 and gp55 gC neutralizing antigens. 
     The DNA segment which encodes RNA translatable to gC polypeptides is identified precisely as follows. VZV DNA is randomly digested and 0.3-1.5 Kbp fragments are inserted into the pORF2 expression vector. Bacteria transformed by the recombinant plasmids are screened with monoclonal antibodies for the production of gC antigens. Plasmid DNA from E. coli expressing gC antigens is hybridized to restriction fragments of VZV genomic DNA, and homology is identified within the HindIII-C fragment. DNA sequence analysis of the VZV DNA within the expression plasmid reveals identity to a 0.9 Kbp segment within the HindIII-C fragment whose DNA sequence is known. This 0.9 Kbp segment is part of a single long 2.0 Kbp open reading frame whose DNA sequence is known and which encodes a 70Kd immunogenic protein. 
     The hybrid protein containing VZV gC sequences derived from the 0.9 Kbp DNA segment is characterized with respect to serological reactivity. It is found to react with 8 of 11 convalescent zoster sera tested as well as with 7 of 8 neutralizing monoclonal antibodies to VZV gC. Therefore, this polypeptide segment carries neutralization epitopes as well as the majority of antigenicity associated with gC polypeptides. 
     Examples of suitable hosts for expression of VZV proteins include prokaryotic organisms, such as E. coli and B. subtilis, and eukaryotic organisms such as S. cerevisiae and continuous mammalian cell lines including Chinese Hamster ovary cells and diploid mammalian fibroblasts such as WI-38 and MRC-5 cells. 
     These proteins are usefully individually or in combination when placed in a physiologically acceptable carrier, e.g., saline or phosphate buffered saline, to protect against VZV disease when administered to a member of a susceptible mammalian species in amount of approximately 10 to 500 μg per dose, preferably from approximately 50 to 25 μg per dose. One or more doses may be administered to produce effective protection against VZV disease. The protein may be administered by injection, e.g., subcutaneously or intramuscularly. It is also to be understood that these proteins can be directly expressed in humans by means of appropriate viral expression vectors such as adeno, vaccinia, or herpes simplex. 
     The following examples illustrate the present invention without, however, limiting the same thereto. The disclosure of each reference mentioned in the following examples is hereby incorporated by reference. 
    
    
     EXAMPLE 1 
     DNA Fragments Which Select RNA Encoding the Precursor Protein to gC glycoproteins 
     Cytoplasmic polyadenylated RNAs were prepared from VZV-infected MRC-5 cells as described (Biochemistry 18: 5294-5299, 1979). The RNAs encoded by the VZV DNA HindIII-C, EcoRI-A and EcoRI-E fragments were selected by hybridization to cloned VZV DNA (Proc. Natl. Acad. Sci. 79: 156-160, 1982) bound to nitrocellulose (J. Virology 37: 284-294, 1981). These RNAs were translated in a rabbit reticulocyte lysate are previously described (Evr. J. Biochem. 67: 247-254, 1976). The polypeptide products were immunoprecipitated with neutralizing monoclonal antibodies specific for VZV gC and with convalescent zoster serum. These DNA fragments select RNAs which include that which translates to the 70Kd gC precursor Okuno et al., Virology 129: 357-368, 1983). 
     EXAMPLE 2 
     Determination of the VZV DNA sequence which encodes gC antigens 
     A library of VZV DNA clones (Proc. Natl. Acad. Sci. 79: 156-160, 1982) was randomly digested by DNaseI in the presence of Mn ++   (Nucleic Acids Research 9: 3015-3027, 1981) in order to produce DNA in the size range of 0.1-2.5 Kbp. From this pool, DNA sized 0.3-1.5 Kbp was purified, made flush-ended, and cloned into the Smal site of the pORF2 expression vector (Proc. Natl. Acad. Sci. 80: 4432-4436, 1983). The recombinant plasmids were introduced into E. coli TK1046 (λ1048). Bacterial colonies expressing hybrid proteins containing VZV polypeptides were selected, and such colonies were screened with monoclonal antibodies for the expression of VZV gC antigens. A colony expressing a VZV gC hybrid protein was isolated. The VZV antigens were recognized by 7 of 8 monoclonal antibodies to gC and by 8 of 11 convalescent zoster sera. The plasmid DNA from this colony was isolated and hybridized to restriction endonuclease digests of VZV genomic DNA (J. Mol. Biol. 98: 503-521, 1975). In this manner, the VZV insert in the bacterial plasmid was shown to be homologous to a 0.9 Kbp DNA sequence in the HindIII-C DNA clone. This segment of HindIII-C DNA, therefore, was identified as a part of the gC gene. 
     EXAMPLE 3 
     Determination of Nucleotide Sequences of the 0.9 and 2.0 Kbp segments of VZV DNA 
     The complete nucleotide sequence of the VZV HindIII-C DNA segment contains several large open reading frames (EMBO Journal 2: 2203-2209, 1983). One of these open reading frames is 2.0 Kbp in length, encodes a 70Kd protein, and contains within it that 0.9 Kbp segment described in Example 2 which encodes VZV gC antigens. 
     A. The nucleotide sequence for the complete 2.0 Kbp segment which encodes the gC glycoprotein is given below: 
     
         __________________________________________________________________________ATG TTT TAT GAA GCC TTA AAG GCC GAG CTG GTA TAC ACGAGA GCA GTC CAT GGT TTT AGA CCT CGG GCG AAT TGC GTGGTT TTA AGT GAC TAT ATT CCG AGG GTC GCC TGT AAT ATGGGG ACA GTT AAT AAA CCT GTG GTG GGG GTA TTG ATG GGGTTC GGA ATT ATC ACG GGA ACG TTG CGT ATA ACG AAT CCGGTC AGA GCA TCC GTC TTG CGA TAC GAT GAT TTT CAC ACCGAT GAA GAC AAA CTG GAT ACA AAC TCC GTA TAT GAG CCTTAC TAC CAT TCA GAT CAT GCG GAG TCT TCA TGG GTA AATCGG GGA GAG TCT TCG CGA AAA GCG TAC GAT CAT AAC TCACCT TAT ATA TGG CCA CGT AAT GAT TAT GAT GGA TTT TTAGAG AAC GCA CAC GAA CAC CAT GGG GTG TAT AAT CAG GGCCGT GGT ATC GAT AGC GGG GAA CGG TTA ATG CAA CCC ACACAA ATG TCT GCA CAG GAG GAT CTT GGG GAC GAT ACG GGCATC CAC GTT ATC CCT ACG TTA AAC GGC GAT GAC AGA CATAAA ATT GTA AAT GTG GAC CAA CGT CAA TAC GGT GAC GTGTTT AAA GGA GAT CTT AAT CCA AAA CCC AAA GGC CAA AGACTC ATT GAG GTG TCA GTG GAA GAA AAT CAC CCG TTT ACTTTA CGC GCA CCG ATT CAG CGG ATT TAT GGA GTC CGG TACACC GAG ACT TGG AGC TTT TTG CCG TCA TTA ACC TGT ACGGGA GAC GCA GCG CCC GCC ATC CAG CAT ATA TGT TTA AAACAT ACA ACA TGC TTT CAA GAC GTG GTG GTG GAT GTG GATTGC GCG GAA AAT ACT AAA GAG GAT CAG TTG GCC GAA ATCAGT TAC CGT TTT CAA GGT AAG AAG GAA GCG GAC CAA CCGTGG ATT GTT GTA AAC ACG AGC ACA CTG TTT GAT GAA CTCGAA TTA GAC CCC CCC GAG ATT GAA CCG GGT GTC TTG AAAGTA CTT CGG ACA GAA AAA CAA TAC TTG GGT GTG TAC ATTTGG AAC ATG CGC GGC TCC GAT GGT ACG TCT ACC TAC GCCACG TTT TTG GTC ACC TGG AAA GGG GAT GAA AAA ACA AGAAAC CCT ACG CCC GCA GTA ACT CCT CAA CCA AGA GGG GCTGAG TTT CAT ATG TGG AAT TAC CAC TCG CAT GTA TTT TCAGTT GGT GAT ACG TTT AGC TTG GCA ATG CAT CTT CAG TATAAG ATA CAT GAA GCG CCA TTT GAT TTG CTG TTA GAG TGGTTG TAT GTC CCC ATC GAT CCT ACA TGT CAA CCA ATG CGGTTA TAT TCT ACG TGT TTG TAT CAT CCC AAC GCA CCC CAATGC CTC TCT CAT ATG AAT TCC GGT TGT ACA TTT ACC TCGCCA CAT TTA GCC CAG CGT GTT GCA AGC ACA GTG TAT CAAAAT TGT GAA CAT GCA GAT AAC TAC ACC GCA TAT TGT CTGGGA ATA TCT CAT ATG GAG CCT AGC TTT GGT CTA ATC TTACAC GAC GGG GGC ACC ACG TTA AAG TTT GTA GAT ACA CCCGAG AGT TTG TCG GGA TTA TAC GTT TTT GTG GTG TAT TTTAAC GGG CAT GTT GAA GCC GTA GCA TAC ACT GTT GTA TCCACA GTA GAT CAT TTT GTA AAC GCA ATT GAA GAG CGT GGATTT CCG CCA ACG GCC GGT CAG CCA CCG GCG ACT ACT AAACCC AAG GAA ATT ACC CCC GTA AAC CCC GGA ACG TCA CCACTT CTA CGA TAT GCC GCA TGG ACC GGA GGG CTT GCA GCAGTA GTA CTT TTA TGT CTC GTA ATA TTT TTA ATC TGT ACGGCT AAA CGA ATG AGG GTT AAA GCC TAT AGG GTA GAC AAGTCC CCG TAT AAC CAA AGC ATG TAT TAC GCT GGC CTT CCAGTG GAC GAT TTC GAG GAC TCG GAA TCT ACG GAT ACG GAAGAA GAG TTT GGT AAC GCG ATT GGA GGG AGT CAC GGG GGTTCG AGT TAC ACG GTG TAT ATA GAT AAG ACC CGG TGA__________________________________________________________________________ 
    
     The foregoing nucleotide sequence codes for the following amino acid sequence: 
     
         ______________________________________M    F       Y     E     A   L     K   A     E   LV    Y       T     R     A   V     H   G     F   RP    R       A     N     C   V     V   L     S   DY    I       P     R     V   A     C   N     M   GT    V       N     K     P   V     V   G     V   LM    G       F     G     I   I     T   G     T   LR    I       T     N     P   V     R   A     S   VL    R       Y     D     D   F     H   T     D   ED    K       L     D     T   N     S   V     Y   EP    Y       Y     H     S   D     H   A     E   SS    W       V     N     R   G     E   S     S   RK    A       Y     D     H   N     S   P     Y   IW    P       R     N     D   Y     D   G     F   LE    N       A     H     E   H     H   G     V   YN    Q       G     R     G   I     D   S     G   ER    L       M     Q     P   T     Q   M     S   AQ    E       D     L     G   D     D   T     G   IH    V       I     P     T   L     N   G     D   DR    H       K     I     V   N     V   D     Q   RQ    Y       G     D     V   F     K   G     D   LN    P       K     P     Q   G     Q   R     L   IE    V       S     V     E   E     N   H     P   FT    L       R     A     P   I     Q   R     I   YG    V       R     Y     T   E     T   W     S   FL    P       S     L     T   C     T   G     D   AA    P       A     I     Q   H     I   C     L   KH    T       T     C     F   Q     D   V     V   VD    V       D     C     A   E     N   T     K   ED    Q       L     A     E   I     S   Y     R   FQ    G       K     K     E   A     D   Q     P   WI    V       V     N     T   S     T   L     F   DE    L       E     L     D   P     P   E     I   EP    G       V     L     K   V     L   R     T   EK    Q       Y     L     G   V     Y   I     W   NM    R       G     S     D   G     T   S     T   YA    T       F     L     V   T     W   K     G   DE    K       T     R     N   P     T   P     A   VT    P       Q     P     R   G     A   E     F   HM    W       N     Y     H   S     H   V     F   SV    G       D     T     F   S     L   A     M   HL    Q       Y     K     I   H     E   A     P   FD    L       L     L     E   W     L   Y     V   PI    D       P     T     C   Q     P   M     R   LY    S       T     C     L   Y     H   P     N   AP    Q       C     L     S   H     M   N     S   GC    T       F     T     S   P     H   L     A   QR    V       A     S     T   V     Y   Q     N   CE    H       A     D     N   Y     T   A     Y   CL    G       I     S     H   M     E   P     S   FG    L       I     L     H   D     G   G     T   TL    K       F     V     D   T     P   E     S   LS    G       L     Y     V   F     V   V     Y   FN    G       H     V     E   A     V   A     Y   TV    V       S     T     V   D     H   F     V   NA    I       E     E     R   G     F   P     P   TA    G       Q     P     P   A     T   T     K   PK    E       I     T     P   V     N   P     G   TS    P       L     L     R   Y     A   A     W   TG    G       L     A     A   V     V   L     L   CL    V       I     F     L   I     C   T     A   KR    M       R     V     K   A     Y   R     V   DK    S       P     Y     N   Q     S   M     Y   YA    G       L     P     V   D     D   F     E   DS    E       S     T     D   T     E   E     E   FG    N       A     I     G   G     S   H     G   GS    S       Y     T     V   Y     I   D     K   T R.______________________________________ 
    
     In the foregoing and succeeding sequences the letters represent the following amino acids: 
     
         ______________________________________A             Ala         AlanineC             Cys         CysteineD             Asp         Aspartic acidE             Glu         Glutamic acidF             Phe         PhenylalanineG             Gly         GlycineH             His         HistidineI             Ile         IsoleucineK             Lys         LysineL             Leu         LeucineM             Met         MethionineN             Asn         AsparagineP             Pro         ProlineQ             Gln         GlutamineR             Arg         ArginineS             Ser         SerineT             Thr         ThreonineV             Val         ValineW             Trp         TryptophanY             Tyr         Tyrosine______________________________________ 
    
     B. The nucleotide sequence for 60 bases at each terminus of the 0.9 Kbp segment was determined and aligned with the published 6.2 Kbp DNA sequence. The 0.9 DNA sequence and the 35Kd gC protein segment, which encodes virtually all the major antigenicity of gC as well as neutralization epitopes, is given below: 
     
         __________________________________________________________________________TTT CAC ACC GAT GAA GAC AAA CTG GAT ACA AAC TCC GTATAT GAG CCT TAC TAC CAT TCA GAT CAT GCG GAG TCT TCATGG GTA AAT CGG GGA GAG TCT TCG CGA AAA GCG TAC GATCAT AAC TCA CCT TAT ATA TGG CCA CGT AAT GAT TAT GATGGA TTT TTA GAG AAC GCA CAC GAA CAC CAT GGG GTG TATAAT CAG GGC CGT GGT ATC GAT AGC GGG GAA CGG TTA ATGCAA CCC ACA CAA ATG TCT GCA CAG GAG GAT CTT GGG GACGAT ACG GGC ATC CAC GTT ATC CCT ACG TTA AAC GGC GATGAC AGA CAT AAA ATT GTA AAT GTG GAC CAA CGT CAA TACGGT GAC GTG TTT AAA GGA GAT CTT AAT CCA AAA CCC CAAGGC CAA AGA CTC ATT GAG GTG TCA GTG GAA GAA AAT CACCCG TTT ACT TTA CGC GCA CCG ATT CAG CGG ATT TAT GGAGTC CGG TAC ACC GAG ACT TGG AGC TTT TTG CCG TCA TTAACC TGT ACG GGA GAC GCA GCG CCC GCC ATC CAG CAT ATATGT TTA AAA CAT ACA ACA TGC TTT CAA GAC GTG GTG GTGGAT GTG GAT TGC GCG GAA AAT ACT AAA GAG GAT CAG TTGGCC GAA ATC AGT TAC CGT TTT CAA GGT AAG AAG GAA GCGGAC CAA CCG TGG ATT GTT GTA AAC ACG AGC ACA CTG TTTGAT GAA CTC GAA TTA GAC CCC CCC GAG ATT GAA CCG GGTGTC TTG AAA GTA CTT CGG ACA GAA AAA CAA TAC TTG GGTGTG TAC ATT TGG AAC ATG CGC GGC TCC GAT GGT ACG TCTACC TAC GCC ACG TTT TTG GTC ACC TGG AAA GGG GAT GAAAAA ACA AGA AAC CCT ACG CCC GCA GTA ACT CCT CAA CCAAGA__________________________________________________________________________ 
    
     The foregoing nucleotide sequence codes for the following amino acid sequence: 
     
         ______________________________________F    H       T     D     E   D     K   L     D   TN    S       V     Y     E   P     Y   Y     H   SD    H       A     E     S   S     W   V     N   RG    E       S     S     R   K     A   Y     D   HN    S       P     Y     I   W     P   R     N   DY    D       G     F     L   E     N   A     H   EH    H       G     V     Y   N     Q   G     R   GI    D       S     G     E   R     L   M     Q   PT    Q       M     S     A   Q     E   D     L   GD    D       T     G     I   H     V   I     P   TL    N       G     D     D   R     H   K     I   VN    V       D     Q     R   Q     Y   G     D   VF    K       G     D     L   N     P   K     P   QG    Q       R     L     I   E     V   S     V   EE    N       H     P     F   T     L   R     A   PI    Q       R     I     Y   G     V   R     Y   TE    T       W     S     F   L     P   S     L   TC    T       G     D     A   A     P   A     I   QH    I       C     L     K   H     T   T     C   FQ    D       V     V     V   D     V   D     C   AE    N       T     K     E   D     Q   L     A   EI    S       Y     R     F   Q     G   K     K   EA    D       Q     P     W   I     V   V     N   TS    T       L     F     D   E     L   E     L   DP    P       E     I     E   P     G   V     L   KV    L       R     T     E   K     Q   Y     L   GV    Y       I     W     N   M     R   G     S   DG    T       S     T     Y   A     T   F     L   VT    W       K     G     D   E     K   T     R   NP    T       P     A     V   T     P   Q     P   R______________________________________ 
    
     Either of the foregoing peptides may be formulated into a vaccine by admixing with a physiologically acceptable carrier and administering parenterally to susceptible mammalian species to induce formation of protective, including neutralizing, antibodies. The dosage level may be from about 5 to about 200 ug in from about one to about 3 doses.