A live-attenuated HSV-2 ICP0 virus elicits 10 to 100 times greater protection against genital herpes than a glycoprotein D subunit vaccine

Glycoprotein D (gD-2) is the entry receptor of herpes simplex virus 2 (HSV-2), and is the immunogen in the pharmaceutical industry''s lead HSV-2 vaccine candidate. Efforts to prevent genital herpes using gD-2 subunit vaccines have been ongoing for 20 years at a cost in excess of $100 million. To date, gD-2 vaccines have yielded equivocal protection in clinical trials. Therefore, using a small animal model, we sought to determine if a live-attenuated HSV-2 ICP0 ⁻ virus would elicit better protection against genital herpes than a gD-2 subunit vaccine. Mice immunized with gD-2 and a potent adjuvant (alum+monophosphoryl lipid A) produced high titers of gD-2 antibody. While gD-2-immunized mice possessed significant resistance to HSV-2, only 3 of 45 gD-2-immunized mice survived an overwhelming challenge of the vagina or eyes with wild-type HSV-2 (MS strain). In contrast, 114 of 115 mice immunized with a live HSV-2 ICP0 ⁻ virus, 0ΔNLS, survived the same HSV-2 MS challenges. Likewise, 0ΔNLS-immunized mice shed an average 125-fold less HSV-2 MS challenge virus per vagina relative to gD-2-immunized mice. In vivo imaging demonstrated that a luciferase-expressing HSV-2 challenge virus failed to establish a detectable infection in 0ΔNLS-immunized mice, whereas the same virus readily infected naïve and gD-2-immunized mice. Collectively, these results suggest that a HSV-2 vaccine might be more likely to prevent genital herpes if it contained a live-attenuated HSV-2 virus rather than a single HSV-2 protein.     

采用我国痘苗病毒天坛株载体表达单纯疱疹病毒Ⅰ型糖蛋白D

木文从单纯疱疹病毒Ⅰ型(HSV-1)基因组EcoRI H片段中分离出含有糖蛋白D(gD)基因的2.5kb DWA片段,插入带有痘苗病毒天坛株TK基因区段的pJC—2质粒p7.5k启动子的下游,转染TK~-143细胞,获得带有HSV-1 gD基因的重组痘苗病毒。采用HSV-1 gD单克隆抗体免疫胶体金技术进行电镜观察表明,重组痘苗病毒感染的细胞内有特异性HSV-1 gD抗原.重组病毒免疫家兔后6周可产生明显的HSV-1中和抗体。     

Immunization with a vaccinia virus recombinant expressing herpes simplex virus type 1 glycoprotein D: long-term protection and effect of revaccination.

Previously we showed that mice immunized with a vaccinia virus vector expressing the herpes simplex virus type 1 (HSV-1) glycoprotein D (gD) gene (vaccinia/gD) were protected against both lethal and latent infections with HSV-1 for at least 6 weeks after immunization (K. J. Cremer, M. Mackett, C. Wohlenberg, A. L. Notkins, and B. Moss, Science 228:737-740, 1985). In the experiments described here, we examined long-term immunity to HSV following vaccinia/gD vaccination, the effect of revaccination with vaccinia/gD, and the impact of previous immunity to vaccinia virus on immunization with the gD recombinant. Mice immunized with vaccinia/gD showed 100, 100, and 80% protection against lethal infection with HSV-1 at 18, 44, and 60 weeks postimmunization, respectively. Protection against latent trigeminal ganglionic infection was 70, 50, and 31% at 6, 41, and 60 weeks postvaccination, respectively. To study the effect of reimmunization on antibody levels, mice vaccinated with vaccinia/gD were given a second immunization (booster dose) 3 months after the first. These mice developed a 10-fold increase in neutralizing-antibody titer (221 to 2,934) and demonstrated a significant increase in protection against lethal HSV-1 challenge compared with animals that received only one dose of vaccinia/gD. To determine whether preexisting immunity to vaccinia virus inhibited the response to vaccination with vaccinia/gD virus, mice were immunized with a recombinant vaccinia virus vector expressing antigens from either influenza A or hepatitis B virus and were then immunized (2 to 3 months later) with vaccinia/gD. These mice showed reduced titers of neutralizing antibody to HSV-1 and decreased protection against both lethal and latent infections with HSV-1 compared with animals vaccinated only with vaccinia/gD. We conclude that vaccination with vaccinia/gD produces immunity against HSV-1 that lasts over 1 year and that this immunity can be increased by a booster but that prior immunization with a vaccinia recombinant virus expressing a non-HSV gene reduces the levels of neutralizing antibody and protective immunity against HSV-1 challenge.     

Herpes simplex virus glycoprotein D mediates interference with herpes simplex virus infection.

We showed that the expression of a single protein, glycoprotein D (gD-1), specified by herpes simplex virus type 1 (HSV-1) renders cells resistant to infection by HSV but not to infection by other viruses. Mouse (LMtk-) and human (HEp-2) cell lines containing the gene for gD-1 under control of the human metallothionein promoter II expressed various levels of gD-1 constitutively and could be induced to express higher levels with heavy metal ions. Radiolabeled viruses bound equally well to gD-1-expressing and control cell lines. Adsorbed viruses were unable to penetrate cells expressing sufficient levels of gD-1, based on lack of any cytopathic effects of the challenge virus and on failure to detect either the induction of viral protein synthesis or the shutoff of host protein synthesis normally mediated by a virion-associated factor. The resistance to HSV infection conferred by gD-1 expression was not absolute and depended on several variables, including the amount of gD-1 expressed, the dosage of the challenge virus, the serotype of the challenge virus, and the properties of the cells themselves. The interference activity of gD-1 is discussed in relation to the role of gD-1 in virion infectivity and its possible role in permitting escape of progeny HSV from infected cells.     

Herpes simplex virus (HSV)-specific human T-cell clones recognize HSV glycoprotein D expressed by a recombinant vaccinia virus.

Human cytotoxic T-cell (CTL) clones that lyse autologous cells infected with herpes simplex virus (HSV) type 1 or 2 were generated by stimulating lymphocytes with a recombinant vaccinia virus (recombinant vaccinia-gD-1 virus) that expresses HSV type 1 glycoprotein D (gD-1). Furthermore, CTL clones generated with HSV type 1 or with cloned gD-1 lysed autologous cells infected with the recombinant vaccinia-gD-1 virus. Our findings thus showed that gD serves as a target antigen for human CTLs and that a recombinant vaccinia-gD virus activates HSV-specific human CTL.     

以痘苗病毒天坛株为载体的表达单纯疱疹病毒Ⅰ型糖蛋白D的重组活疫苗的建立

从我国分离到的一株单纯疱疹病毒Ⅰ型（ＨＳＶ－１－１６８株）病毒基因组中,分离出含有糖蛋白Ｄ（ｇＤ）基因的１．２ｋｂ片段,插入带有痘苗病毒天坛株ＴＫ区的质粒ｐＪＳＢ１１７５Ｐ７．５ｋ启动子下游,转染无白血病鸡胚原代细胞,获得带有ＨＳＶ－１－１６８ｇＤ基因的重组痘苗病毒。此株重组病毒在感染细胞膜上表达ＨＳＶ－１－１６８ｇＤ糖蛋白抗原,能与特异性单克隆抗体反应。在感染细胞中表达的膜抗原经ＳＤＳ－ＰＡＧＥ分析,表达分子量为５４ｋＤ糖蛋白。用Ｓｏｕｔｈｅｒｎ杂交分析了重组病毒ＤＮＡ中特异的ｇＤ基因,对作为活疫苗的重组痘苗病毒株进行了一些微生物学活性、免疫原性和毒力等方面的研究。     

Human cytotoxic T cell clones directed against herpes simplex virus-infected cells. III. Analysis of viral glycoproteins recognized by CTL clones by using recombinant herpes simplex viruses

Human cytotoxic T cell (CTL) clones specific for herpes simplex virus (HSV) type 1- and type 2-infected cells were generated and were analyzed with regard to the viral glycoproteins they recognize on autologous HSV-infected cells. By use of target cells infected with wild-type HSV strains, a gC deletion mutant of HSV-1, and HSV-1 X HSV-2 intertypic recombinants, some HSV-1-specific CTL clones were found to be directed against L region-encoded gA/B-1, and others against S region-encoded glycoproteins (gD-1 or gE-1). Some HSV-2-specific clones were found to be directed against L region-encoded gC-2, whereas others were directed against S region-encoded glycoproteins (gD-2, gE-2, or gG). These findings provide direct evidence that several HSV glycoproteins that are expressed on the surface of HSV-infected cells serve as recognition structures for human HSV-specific CTL.     

Cells expressing herpes simplex virus glycoprotein gC but not gB, gD, or gE are recognized by murine virus-specific cytotoxic T lymphocytes

To determine which viral molecule(s) is recognized by herpes simplex virus (HSV)-specific cytotoxic T lymphocytes (CTL), target cells were constructed which express individual HSV glycoproteins. A mouse L cell line, Z4/6, which constitutively expressed high levels of HSV type 2 (HSV-2) gD (gD-2) was isolated and characterized previously (D. C. Johnson and J. R. Smiley, J. Virol. 54:682-689, 1985). Despite the expression of gD on the surface of Z4/6 cells, these cells were not killed by anti-HSV-2 CTL generated following intravaginal infection of syngeneic mice. In contrast, parental Z4 or Z4/6 cells infected with HSV-2 were lysed. Furthermore, unlabeled Z4/6 cells were unable to block the lysis of HSV-2-infected labeled target cells. Cells which express HSV-1 gB (gB-1) were isolated by transfecting L cells with the recombinant plasmid pSV2gBneo, which contains the HSV-1 gB structural sequences and the neomycin resistance gene coupled to the simian virus 40 early promoter and selecting G418-resistant cell lines. One such cell line, Lta/gB15, expressed gB which was detected by immunoprecipitation and at the cell surface by immunofluorescence. Additionally, cells expressing HSV-1 gC (gC-1) or gE (gE-1) were isolated by transfecting Z4 cells, which are L cells expressing ICP4 and ICP47, with either the recombinant plasmid pGE15neo, which contains the gE structural sequences and the neomycin resistance gene, or pDC17, which contains the gC structural gene coupled to the gD-1 promoter. A number of G418-resistant cell lines were isolated which expressed gC-1 or gE-1 at the cell surface. Anti-HSV-1 CTL generated following footpad infection of syngeneic mice were unable to lyse target cells expressing gB-1 or gE-1. In contrast, target cells expressing very low levels of gC-1 were killed as well as HSV-1-infected target cells. Furthermore, infection of gC-1-transformed target cells with wild-type HSV-1 or a strain of HSV-1 that does not express gC did not result in a marked increase in susceptibility to lysis. These results suggest that murine class I major histocompatibility complex-restricted anti-HSV CTL recognize gC-1 but do not recognize gB, gD, or gE as these molecules are expressed in transfected syngeneic target cells. The results are discussed in terms of recent evidence concerning the specificity of antiviral CTL.     

The gH-gL Complex of Herpes Simplex Virus (HSV) Stimulates Neutralizing Antibody and Protects Mice against HSV Type 1 Challenge

The herpes simplex virus type 1 (HSV-1) gH-gL complex which is found in the virion envelope is essential for virus infectivity and is a major antigen for the host immune system. However, little is known about the precise role of gH-gL in virus entry, and attempts to demonstrate the immunologic or vaccine efficacy of gH and gL separately or as the gH-gL complex have not succeeded. We constructed a recombinant mammalian cell line (HL-7) which secretes a soluble gH-gL complex, consisting of gH truncated at amino acid 792 (gHt) and full-length gL. Purified gHt-gL reacted with gH- and gL-specific monoclonal antibodies, including LP11, which indicates that it retains its proper antigenic structure. Soluble forms of gD (gDt) block HSV infection by interacting with specific cellular receptors. Unlike soluble gD, gHt-gL did not block HSV-1 entry into cells, nor did it enhance the blocking capacity of gD. However, polyclonal antibodies to the complex did block entry even when added after virus attachment. In addition, these antibodies exhibited high titers of complement-independent neutralizing activity against HSV-1. These sera also cross-neutralized HSV-2, albeit at low titers, and cross-reacted with gH-2 present in extracts of HSV-2-infected cells. To test the potential for gHt-gL to function as a vaccine, BALB/c mice were immunized with the complex. As controls, other mice were immunized with gD purified from HSV-infected cells or were sham immunized. Sera from the gD- or gHt-gL-immunized mice exhibited high titers of virus neutralizing activity. Using a zosteriform model of infection, we challenged mice with HSV-1. All animals showed some evidence of infection at the site of virus challenge. Mice immunized with either gD or gHt-gL showed reduced primary lesions and exhibited no secondary zosteriform lesions. The sham-immunized control animals exhibited extensive secondary lesions. Furthermore, mice immunized with either gD or gHt-gL survived virus challenge, while many control animals died. These results suggest that gHt-gL is biologically active and may be a candidate for use as a subunit vaccine.     

Human cytotoxic T cell clones directed against herpes simplex virus-infected cells. IV. Recognition and activation by cloned glycoproteins gB and gD

Results of studies in mice and clinical observations in man indicate that T cell-mediated immunity is important in resistance to herpes simplex virus (HSV) infections. This study was undertaken to elucidate the viral antigen specificity of human HSV-immune T cells. Purified HSV-1 glycoproteins gB-1 and gD-1, cloned and expressed in mammalian cells, were found to stimulate proliferation of, and interleukin 2 (IL 2) production by, peripheral blood lymphocytes (PBL) of HSV seropositive individuals, indicating the presence of memory T cells to gB-1 and gD-1 in individuals with serologic evidence of immunity to HSV. Second, T cell clones, generated by stimulation of PBL with HSV-1, were found to recognize gB-1 or gD-1, as evidenced by the ability of the clones to proliferate in response to stimulation with gB-1 or gD-1 in the absence of exogenous IL 2. Third, HSV-specific T cell clones, lytic for HSV-1 or both HSV-1- and HSV-2-infected autologous target cells, were generated after stimulation of PBL with purified cloned gB-1 or gD-1. Our findings, that human HSV-specific T cells can recognize and be activated by HSV subunit antigens gB-1 or gD-1, imply that these glycoproteins play a role in human T cell-mediated immunity to HSV and support the contention that a gB-1 or gD-1 subunit vaccine may be protective in man.     

Vaccinia virus recombinants expressing the SA11 rotavirus VP7 glycoprotein gene induce serotype-specific neutralizing antibodies.

A cDNA copy of the gene coding for the major outer neutralizing protein (VP7) of simian 11 rotavirus was incorporated into the vaccinia virus genome under the control of the vaccinia promoter (molecular weight, 7,500). A deletion mutant of this gene which codes for a secreted form of VP7 when expressed under the control of the simian virus 40 late promoter (M. S. Poruschynsky, C. Tyndall, G. W. Both, F. Sato, A. R. Bellamy, and P. H. Atkinson, J. Cell Biol. 101:2199-2209, 1985) was also inserted. Each recombinant vaccinia virus directed the synthesis of a rotavirus protein in infected cells, and the product encoded by the mutated gene was secreted. Rabbits immunized with the two types of recombinant vaccinia virus generated antibodies that were able both to recognize simian 11 rotavirus in an enzyme-linked immunosorbent assay and to neutralize the virus in a plaque-reduction test. Antibodies induced by the recombinant vaccinia viruses expressing either form of VP7 were serotype specific.     

The mechanisms of antiviral immunity induced by a vaccinia virus recombinant expressing herpes simplex virus type 1 glycoprotein D: clearance of local infection

We have shown that immunization of mice with a vaccinia virus recombinant expressing glycoprotein D of Herpes simplex virus (HSV)-1 will induce a variety of L3T4+ T cell responses. These included a HSV-specific delayed-type hypersensitivity response, T cell help for the induction of antiviral antibodies, and the ability to eliminate a challenge dose of HSV from the pinna. This protection against a subcutaneous virus challenge was not mediated by the delayed-type hypersensitivity response because intravenous inoculation of the vaccinia virus recombinant expressing HSV-1-gD induced a state of split tolerance. Thus, mice could still clear a HSV challenge inoculum from the pinna yet were unable to mount a HSV-specific delayed-type hypersensitivity response. Evidence is presented that suggests the protective response was, at least, in part mediated by a T cell-dependent induction of virus-neutralizing antibodies. Evidence is also presented that may suggest the failure of a vaccinia virus recombinant expressing HSV-1-gD to induce HSV-specific cytotoxic T cell responses appears to minimize the protective response to only efficiently clearing low 10(4) 50% tissue culture infective dose) challenge populations of virus. These findings are discussed with relevance to the immune control of HSV infections and to the future development of anti-HSV vaccines.     

Functional interaction between herpes simplex virus type 2 gD and HVEM transiently dampens local chemokine production after murine mucosal infection

Herpes virus entry mediator (HVEM) is one of two principal receptors mediating herpes simplex virus (HSV) entry into murine and human cells. It functions naturally as an immune signaling co-receptor, and may participate in enhancing or repressing immune responses depending on the natural ligand used. To investigate whether engagement of HVEM by HSV affects the in vivo response to HSV infection, we generated recombinants of HSV-2(333) that expressed wild-type gD (HSV-2/gD) or mutant gD able to bind to nectin-1 (the other principal entry receptor) but not HVEM. Replication kinetics and yields of the recombinant strains on Vero cells were indistinguishable from those of wild-type HSV-2(333). After intravaginal inoculation with mutant or wild-type virus, adult female C57BL/6 mice developed vaginal lesions and mortality in similar proportions, and mucosal viral titers were similar or lower for mutant strains at different times. Relative to HSV-2/gD, percentages of HSV-specific CD8(+) T-cells were similar or only slightly reduced after infection with the mutant strain HSV-2/gD-Δ7-15, in all tissues up to 9 days after infection. Levels of HSV-specific CD4(+) T-cells five days after infection also did not differ after infection with either strain. Levels of the cytokine IL-6 and of the chemokines CXCL9, CXCL10, and CCL4 were significantly lower in vaginal washes one day after infection with HSV-2/gD compared with HSV-2/gD-Δ7-15. We conclude that the interaction of HSV gD with HVEM may alter early innate events in the murine immune response to infection, without significantly affecting acute mortality, morbidity, or initial T-cell responses after lethal challenge.     

The dominant-negative herpes simplex virus type 1 (HSV-1) recombinant CJ83193 can serve as an effective vaccine against wild-type HSV-1 infection in mice

By selectively regulating the expression of the trans-dominant-negative mutant polypeptide UL9-C535C, of herpes simplex virus type 1 (HSV-1) origin binding protein UL9 with the tetracycline repressor (tetR)-mediated gene switch, we recently generated a novel replication-defective and anti-HSV-specific HSV-1 recombinant, CJ83193. The UL9-C535C peptides expressed by CJ83193 can function as a potent intracellular therapy against its own replication, as well as the replication of wild-type HSV-1 and HSV-2 in coinfected cells. In this report, we demonstrate that CJ83193 cannot initiate acute productive infection in corneas of infected mice nor can it reactivate from trigeminal ganglia of mice latently infected by CJ83193 in a mouse ocular model. Given that CJ83193 is capable of expressing the viral alpha, beta, and gamma1 genes but little or no gamma2 genes, we tested the vaccine potential of CJ83193 against HSV-1 infection in a mouse ocular model. Our studies showed that immunization with CJ83193 significantly reduced the yields of challenge HSV in the eyes and trigeminal ganglia on days 3, 5, and 7 postchallenge. Like in mice immunized with the wild-type HSV-1 strain KOS, immunization of mice with CJ83193 prevents the development of keratitis and encephalitis induced by corneal challenge with wild-type HSV-1 strain mP. Delayed-type hypersensitivity (DTH) assays demonstrate that CJ83193 can elicit durable cell-mediated immunity at the same level as that of wild-type HSV-1 and is more effective than that induced by d27, an HSV-1 ICP27 deletion mutant. Moreover, mice immunized with CJ83193 developed strong, durable HSV-1-neutralizing antibodies at levels at least twofold higher than those induced by d27. The results presented in this report have shed new light on the development of effective HSV viral vaccines that encode a unique safety mechanism capable of inhibiting the mutant's own replication and that of wild-type virus.     

High level expression and secretion of truncated forms of herpes simplex virus type 1 and type 2 glycoprotein D by the methylotrophic yeast Pichia pastoris

Herpes simplex virus type 1 and 2 (HSV-1 and -2) glycoproteins D (gD-1 and gD-2) play a role in the entry of the virus into the host cell. Availability of substantial amounts of these proteins, or large fragments thereof, will be needed to allow studies at the molecular level. We studied the potency of the Pichia pastoris yeast expression system to produce soluble forms of gD. The DNA sequences encoding the extracellular domains of gD [amino acids 1-314 (gD-1(1-314)) and amino acids 1-254 (gD-1(1-254)) of gD-1 and amino acids 1-314 of gD-2 (gD-2(1-314))] were cloned into the P. pastoris yeast expression vector pPIC9. Two truncated forms of gD-1 were fitted with a His tail (designated as gD-1(1-314His) and gD-1(1-254His)) to facilitate their purification. Large amounts of gD-1(1-314) and gD-1(1-314His) (280-300mg/L induction medium) were produced. The yields of recombinant gD-1(1-254) and gD-1(1-254His) were lower: 20-36mg/L, and the yield of the gD-2(1-314) fragment was much lower: 6mg/L. SDS-PAGE analysis revealed multiple glycosylated species of the larger gD fragments, ranging in apparent molecular weight from 31 to 78kDa. The smaller gD-1(1-254) fragment appeared as two bands with molecular weights of 33 and 31kDa. All recombinant proteins produced by P. pastoris were recognized, as expected, by a panel of MAbs (A16, DL6, A18, DL11, HD1, ABDI, and AP7). In addition, we showed that gD-1(1-314), gD-2(1-314), and gD-1(1-254His) were able to interfere with binding of HSV to susceptible cells. These results indicate that the conformations of the recombinant proteins closely resemble those of native gD.     

Comparison of adjuvant efficacy of herpes simplex virus type 1 recombinant viruses expressing TH1 and TH2 cytokine genes

The adjuvant effects of cytokines in humoral and cell-mediated immunity to herpes simplex virus type 1 (HSV-1) have been examined in mice using HSV-1 recombinant viruses expressing murine interleukin-2 (IL-2), IL-4, or gamma interferon (IFN-gamma) gene. Groups of naive BALB/c mice were immunized intraperitoneally with one or three doses of the HSV-1 recombinant viruses expressing IL-2, IL-4, or IFN-gamma or with parental control virus. Despite similar replication kinetics, these three recombinant viruses elicited different immune responses to HSV-1 on immunization. Immunization with the recombinant virus expressing IL-4 elicited a humoral response of greater magnitude than immunization with the recombinant viruses expressing IL-2 or IFN-gamma or with parental virus. In contrast, immunization with recombinant virus expressing IL-2 elicited a higher cytotoxic T-cell response than immunization with viruses expressing IL-4 or IFN-gamma. Stimulation in vitro of splenocytes obtained from the mice immunized with UV-inactivated HSV-1 McKrae resulted in a T(H)1 pattern of cytokine expression irrespective of the recombinant virus used in the immunization. As observed for the parental virus, both CD4(+) and CD8(+) T cells contributed equally to the production of IL-2 by the splenocytes of mice immunized with any of the three recombinant viruses. However, the pattern of IFN-gamma production by CD4(+) and CD8(+) T cells differed according to the recombinant virus used. After lethal ocular challenge, all immunized mice were protected completely against death and manifestations of eye disease caused by HSV-1, which are typical responses in unimmunized mice. Mice immunized with IL-4-expressing virus cleared the virus from their eyes more rapidly than mice immunized with IL-2- or IFN-gamma-expressing virus. Taken together, our results suggest that, in contrast to IFN-gamma which did not exhibit an adjuvant effect, both IL-4 and IL-2 act as adjuvants in immunization with HSV, with IL-4 showing greater efficacy.     

B7 costimulation molecules expressed from the herpes simplex virus 2 genome rescue immune induction in B7-deficient mice

The interaction between B7 costimulation molecules on antigen-presenting cells and CD28 on antigen-responsive T cells is essential for T-cell activation and maturation of immune responses to herpes simplex virus (HSV) infection. Vaccine-induced immune responses also depend upon adequate upregulation of B7 costimulation molecules, but this signal may be limiting for replication-defective virus vaccines. We investigated whether expression of B7 costimulation molecules by a prototypical replication-defective antiviral vaccine could enhance immune responses to the vaccine and whether B7-1 and B7-2 would be similarly effective. We altered an ICP8(-) replication-defective strain of HSV type 2 (HSV-2), 5BlacZ, to encode either murine B7-1 or B7-2. B7 molecule expression was detected on the surface of cells infected in vitro and at the RNA level in tissue of immunized mice. Immunization of B7-1/B7-2 knockout mice with B7-encoding virus modestly expanded the number of gamma interferon-producing T cells and significantly augmented class-switched HSV-specific antibody responses compared with the parental virus. Mice immunized with either B7-expressing virus showed less replication of challenge virus in the genital mucosa than mice immunized with 5BlacZ, markedly fewer signs of genital and neurological disease, and little weight loss. Virtually all mice immunized with B7-encoding virus survived challenge with a large dose of HSV-2, whereas most 5BlacZ-immunized mice succumbed to infection. These results indicate that protective immune responses can be enhanced by the inclusion of host B7 costimulation molecules in a prototypical replication-defective HSV vaccine against HSV-2 genital infection and that B7-1 and B7-2 induce immune responses with similar capacities to fight HSV-2 infection.     

Retention of the herpes simplex virus type 1 (HSV-1) UL37 protein on single-stranded DNA columns requires the HSV-1 ICP8 protein.

The UL37 and ICP8 proteins present in herpes simplex virus type 1 (HSV-1)-infected-cell extracts produced at 24 h postinfection coeluted from single-stranded-DNA-cellulose columns. Experiments carried out with the UL37 protein expressed by a vaccinia virus recombinant (V37) revealed that the UL37 protein did not exhibit DNA-binding activity in the absence of other HSV proteins. Analysis of extracts derived from cells coinfected with V37 and an ICP8-expressing vaccinia virus recombinant (V8) and analysis of extracts prepared from cells infected with the HSV-1 ICP8 deletion mutants d21 and n10 revealed that the retention of the UL37 protein on single-stranded DNA columns required a DNA-binding-competent ICP8 protein.     

Localization and synthesis of an antigenic determinant of herpes simplex virus glycoprotein D that stimulates the production of neutralizing antibody.

An antigenic determinant capable of inducing type-common herpes simplex virus (HSV)-neutralizing antibodies has been located on glycoprotein D (gD) of HSV type 1 (HSV-1). A peptide of 16 amino acids corresponding to residues 8 to 23 of the mature glycoprotein (residues 33 to 48 of the predicted gD-1 sequence) was synthesized. This peptide reacted with an anti-gD monoclonal antibody (group VII) previously shown to neutralize the infectivity of HSV-1 and HSV-2. The peptide was also recognized by polyclonal antibodies prepared against purified gD-1 but was less reactive with anti-gD-2 sera. Sera from animals immunized with the synthetic peptide reacted with native gD and neutralized both HSV-1 and HSV-2.     

Pan-HSV-2 IgG Antibody in Vaccinated Mice and Guinea Pigs Correlates with Protection against Herpes Simplex Virus 2

We lack a correlate of immunity to herpes simplex virus 2 (HSV-2) that may be used to differentiate whether a HSV-2 vaccine elicits robust or anemic protection against genital herpes. This gap in knowledge is often attributed to a failure to measure the correct component of the adaptive immune response to HSV-2. However, efforts to identify a correlate of immunity have focused on subunit vaccines that contain less than 3% of HSV-2''s 40,000-amino-acid proteome. We were interested to determine if a correlate of immunity might be more readily identified if 1. animals were immunized with a polyvalent immunogen such as a live virus and/or 2. the magnitude of the vaccine-induced immune response was gauged in terms of the IgG antibody response to all of HSV-2''s antigens (pan-HSV-2 IgG). Pre-challenge pan-HSV-2 IgG levels and protection against HSV-2 were compared in mice and/or guinea pigs immunized with a gD-2 subunit vaccine, wild-type HSV-2, or one of several attenuated HSV-2 ICP0 ⁻ viruses (0Δ254, 0Δ810, 0ΔRING, or 0ΔNLS). These six HSV-2 immunogens elicited a wide range of pan-HSV-2 IgG levels spanning an ∼500-fold range. For 5 of the 6 immunogens tested, pre-challenge levels of pan-HSV-2 IgG quantitatively correlated with reductions in HSV-2 challenge virus shedding and increased survival frequency following HSV-2 challenge. Collectively, the results suggest that pan-HSV-2 IgG levels may provide a simple and useful screening tool for evaluating the potential of a HSV-2 vaccine candidate to elicit protection against HSV-2 genital herpes.