Humoral and Cellular Immunity to Varicella-Zoster Virus Glycoprotein gpI and to a Non-glycosylated Protein, p170, in the Strain 2 Guinea-pig

Abstract

SUMMARYStrain 2 guinea-pigs were inoculated with infectious varicella-zoster virus (VZV) or with immunoaflinity-purified proteins of VZV. Monoclonal antibodies to the VZV gpI (90000/58 000 complex) and to a non-glycosylated protein, p170, were used to prepare the polypeptide antigens. Humoral and cell-mediated immune responses to the infectious virus were compared with those elicited by the gpI and p170 proteins. Both VZV IgG antibody production and T lymphocyte proliferation to VZV were detected after immunization with infectious VZV and with VZV proteins. The antibody and T lymphocyte responses waned after protein immunization in comparison with the responses induced by infectious VZV but were detected again immediately after reimmunization with gpI or p170.The study of the pathogenesis of varicella-zoster virus (VZV) infection is hampered by the lack of an appropriate animal model. Simian variceUa virus is antigenically related to human VZV but the disease caused by the former in primates is usually much more severe than VZV infection in the healthy human host (Arvin et al., 1983). Although infection of the guinea-pig with VZV does not produce disease, Myers et al. (1985) observed that human VZV passaged in foetal guinea-pig tissue culture caused viraemia and nasopharyngeal infection in weanling guinea-pigs. Antibodies to viral proteins of 62000, 98000 and 118000 Mr detected by immunoprecipitation with sera from VZV-immune human subjects were also observed by immunoprecipitation with guinea-pig sera (Grose & Friedrichs, 1982). Matsunaga et al. (1982) showed that guinea-pigs inoculated with VZV adapted to guinea-pig cells developed delayed hypersensitivity to VZV antigen as well as VZV-specific antibodies.In the present study, the immunogenic potentials of a major VZV glycoprotein, gpI (Davison et al., 1986), and of a non-glycosylated protein, p170, were evaluated in the strain 2 guinea-pig and compared with the immune response after inoculation with infectious VZV. The strain 2 guinea-pig was used for these immunological studies because of its potential value for the study of VZV pathogenesis in relation to the immune response.The animals were weanling strain 2 guinea-pigs obtained from the Charles River Caviary, Charles River Breeding Laboratories, Wilmington, Mass. and the National Cancer Institute, Bethesda, Md., U.S.A. and weighed approximately 250 g at the time of the initial inoculation. The animals that received infectious VZV were inoculated with guinea-pig-adapted VZV. Foetal guinea-pig cell lines were established from guinea-pig embryos of 1.0 to 1-5 cm (Edmond et al., 1981). The cells were grown in ME M with 10 ~ foetal calf serum and were used to prepare VZV-infected cells for up to six passages. A VZV isolate from a cutaneous varicella vesicle was passed ten times in guinea-pig embryo cells. Guinea-pig cell-adapted VZV was stored at -70 °C and passed once more in guinea-pig embryo cells immediately before use. Animals given 0000-7694 © 1987 SGM

Immunity in strain 2 guinea-pigs inoculated with vaccinia virus recombinants expressing varicella-zoster virus glycoproteins I, IV, V or the protein product of the immediate early gene 62

“…As noted in strain 2 guinea-pigs given immunoaffinitypurified gpI or IE-62 protein, the initial exposure to VZV gpI, gpIV, gpV or IE-62 expressed by vaccinia virus recombinants primed the host response of strain 2 guinea-pigs so that a significant boost in cell-mediated immunity was elicited by inoculation with guinea-pig cell-adapted VZV (Arvin et al, 1987). Enhanced T cell proliferation could be attributed to the failure of vac-gpV immunization to restrict the replication of the challenge virus.…”

“…VZV infection also induces antibodies with neutralizing activity and antibodies that immunoprecipitate the same VZV-infected cell proteins as human immune sera (Grose & Friedrichs, 1982). With regard to the viral protein specificity of the immune response, immunoaffinity-purified glycoprotein I (gpI) and an immediate early (IE) protein (IE-62) were found to be immunogenic in strain 2 guinea-pigs (Arvin et al, 1987). These proteins are also targets of persistent immunity to VZV in human subjects following wild-type virus infection and after immunization with the Oka/Merck variceUa vaccine (Arvin et al, 1986bDiaz et al, 1988).…”

“…Since cell-mediated immunity is critical in the human host response to VZV, the fact that VZV-specific T cell proliferation and delayed hypersensitivity responses to VZV antigens are elicited by VZV infection makes the guinea-pig model especially useful (Matsunaga et al, 1982;Arvin et al, 1986aArvin et al, , 1987. T lymphocyte-mediated cytotoxicity against histocompatibility-matched, VZVinfected target cells can be demonstrated by infecting inbred guinea-pig strains with VZV (Hayward et al, 1991).…”

“…was calculated as the ratio of mean c.p.m, in duplicate antigen-stimulated wells to the mean c.p.m, in duplicate control wells, with an S.I. > 2.0 being considered positive (Arvin et al, 1987). Each assay included positive control wells stimulated with phytohaemagglutinin.…”

“…VZV-specific T lymphocyte proliferation was determined by incubating peripheral blood mononuclear cells, obtained by cardiac puncture and separated with FicollHypaque, with VZV antigen or an uninfected cell control in 96-well microtitre plates (Arvin et al, 1987). The cells were cultured at a concentration of 3 x 105 cells/0.2 ml per well in RPMI medium with 10% guinea-pig serum, 2-mercaptoethanol and 5% NaHCO 3.…”