Celine M. Koropchak

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

The immunogenicity of specific varicella-zoster virus (VZV) proteins, with emphasis upon cell-mediated immune responses, was evaluated by immunizing strain 2 guinea-pigs with vaccinia virus recombinants that express gpI (vac-gpI), gpIV (vac-gpIV) and gpV (vac-gpV) or the IE-62 protein (vac-IE-62). Vac-gpI elicited the highest initial mean T cell proliferation response [stimulation index (S.I.) 3.8 +/- 0.9 S.E.M.] whereas inoculation with vac-gpV produced the lowest primary T cell response (S.I. 2.5 +/- 1.1 S.E.M.). T cell proliferation was detected for a shorter period after immunization with vac-gpV compared to vac-gpI, vac-gpIV or vac-IE-62. A comparison of the immunogenicity of vac-gpI and vac-IE-62 with the same proteins prepared by immunoaffinity purification showed that immunization with these proteins in either form elicited virus-specific IgG antibodies and T cell recognition. The presence or absence of IgG antibodies to the IE-62 protein was used to assess protection against challenge with guinea-pig cell-adapted infectious VZV in animals that had been inoculated with vac-gpI, vac-gpIV or vac-gpV. Immunization with vac-gpI and vac-gpIV restricted VZV replication but all animals given vac-gpV developed antibodies to IE-62 after challenge with infectious VZV. Priming of the T lymphocyte response was observed in all animals immunized with VZV-vaccinia virus recombinants after subsequent exposure to infectious VZV. These experiments with VZV vac-gpI, vac-gpIV and vac-gpV in guinea-pigs suggest variability in the capacity of herpesviral glycoproteins to elicit cell-mediated immunity in vivo. Induction of virus-specific immunity using IE-62 means that this major tegument protein of VZV could be a useful component for vaccine development.

Comparison of varicella zoster antibody titers in patients given intravenous immune serum globulin or varicella zoster immune globulin

We compared the VZV IgG antibody titers after administration of varicella zoster immune globulin and serum immune globulin intravenously (IGIV) in VZV seronegative pediatric patients with cancer. Four patients received VZIG at standard doses; four received IGIV at 4 ml/kg every 4 weeks for four doses; and five received IGIV at 6 ml/kg every 6 weeks for two to four doses. VZV antibody titers were measured by radiommunoassay (RIA), enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibody assay (IFA), and neutralizing antibody assay. The mean peak and trough VZV titers by RIA were comparable in all three groups: 1:724 at 4 weeks after VZIG, 1:2048 at 4 weeks after 4 ml/kg IGIV, and 1:776 at 6 weeks after 6 ml/kg IGIV. The titers measured by ELISA, IFA, and neutralizing antibody were comparable after VZIG or IGIV. The VZV titers by RIA were maintained at greater than or equal to 1:1024 after subsequent doses of 4 ml/kg IGIV, and at greater than or equal to 1:256 after subsequent doses of 6 ml/kg IGIV. Adverse effects were rare. The VZV antibody titers assessed 4 to 6 weeks after IGIV administration were equivalent to the titers measured 4 weeks after administration of VZIG.

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

Strain 2 guinea-pigs were inoculated with infectious varicella-zoster virus (VZV) or with immunoaffinity-purified proteins of VZV. Monoclonal antibodies to the VZV gpI (90,000/58,000 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.

Investigation of varicella-zoster virus-infected cell proteins that elicit antibody production during primary varicella using the immune transfer method

The varicella-zoster virus-infected cell proteins (VZV-ICPs) against which IgG, IgM and IgA antibodies were made in the course of primary varicella-zoster virus (VZV) infection were analysed by the immune transfer method. IgG antibodies were made against one or more of 18 VZV-ICPs by patients with varicella. IgM antibodies were produced which reacted with 21 VZV-ICPs. The spectrum of IgG antibody production during the first week after the onset of infection was limited to an average of three VZV-ICPs while IgM antibodies which reacted with an average of seven VZV-ICPs were detectable in the acute phase of varicella. Equivalent VZV IgG or IgM antibody titres by radioimmunoassay did not correlate with a similar pattern of antibody specificity for VZV-ICPs by immune transfer. A detectable immune response to all VZV-ICPs was not required for the recovery of individual patients from primary VZV infection.

Varicella zoster antibody titers after the administration of intravenous immune serum globulin or varicella zoster immune globulin

Varicella is a serious infection in the immunocompromised patient. Prophylaxis with varicella zoster immune globulin is known to decrease the incidence of severe varicella infection. The titers of antibody to varicella zoster virus were compared in patients who received either varicella zoster immune globulin or intravenous immune globulin, 4 ml or 6 ml/kg per dose. The titers of antibody to varicella zoster virus were comparable in each group.

The synthesis and immunogenicity of varicella-zoster virus glycoprotein E and immediate-early protein (IE62) expressed in recombinant herpes simplex virus-1.

In order to evaluate the conditions for optimal expression and immunogenicity of varicella-zoster virus (VZV) proteins in a herpes simplex virus-1 (HSV-1) vector, we selected the VZV glycoprotein E (gE), encoded by ORF 68 and the VZV product of ORF 62, an immediate-early major tegument protein (IE62). Three HSV/VZV recombinants were generated: (1) VZV gE protein coding sequences along with the promoter region were inserted into the thymidine kinase (TK) gene of HSV-1 strain KOS; (2) VZV gE expressed from the HSV-1 ICP4 promoter was inserted into the glycoprotein C (gC) gene of HSV-1 strain F; and (3) VZV IE62 protein coding sequences under the control of the HSV-1 ICP4 promoter were inserted into the gC gene of HSV-1 strain F. Immunoblot analysis and immunoperoxidase staining of infected cell monolayers demonstrated vector expression of VZV proteins. Following intracranial inoculation in mice, both VZV gE-HSV (TK) and VZV IE62-HSV (gC) induced an IgG response against VZV gE or VZV IE62. When tested in cytotoxicity assays using T-lymphocytes from VZV immune human donors, the range of precursor frequencies for T-lymphocytes that recognized VZV gE or VZV IE62 was similar whether these proteins were expressed by HSV-1 or a vaccinia vector. These experiments demonstrate that HSV-1 is a competent vector for expression of these VZV proteins and support the feasibility of engineering a combined vaccine for these closely related alpha-herpesviruses.