Immunization against viral pathogens is generally directed toward the induction of virus neutralizing antibody (VNA) and the maintenance of the potential for a second-set (IgG) response. Indeed, an elevated level of specific antibody is considered a reliable clinical indicator that a state of immunity exists in the host. However, in the case of herpes simplex virus (HSV), the presence of circulating VNA does not necessarily correlate with protection. Thus, it has been found that secondary infections occur in individuals even with high neutralizing titers to HSV, suggesting that antibody to the virus may be useless or even deleterious. In consideration of these facts, we were interested in inducing a T cell response to HSV. We had already shown that synthetic peptides corresponding to the NH3-terminal region of the glycoprotein D (gD) molecule of HSV could induce a strong T cell response when injected into mice, but did not, by themselves, confer protection. In this report, we examined the ability of peptides, covalently coupled to palmitic acid and incorporated into liposomes, to induce virus-specific T cell responses that confer protection against a lethal challenge of HSV-2. We have demonstrated that long-term protective immunity is achieved with a single immunization in the absence of neutralizing antibody when antigen is presented in this form. Furthermore, T cells but not serum from such immune mice can adoptively transfer this protection.

Monoclonal antibodies (MAbs) that neutralized human cytomegalovirus (HCMV) were produced by ten hybrid cells lines, generated from BALB/c mice immunized with HCMV-infected human fibroblasts. By immunoblot technique six antibodies detected a set of HCMV glycosylated polypeptides which, when separated under reducing conditions, migrated with apparent molecular weights (m.wt.) of 47.5K, 51K, 54K, 58K, and 60-69K. One other antibody reacted only with the 47.5 and 51K polypeptides and the 60-69K broad band. Under nonreducing conditions, these antibodies showed no reactivity with any polypeptide. The three remaining MAbs reacted with two high-m.wt. polypeptides of approximately 200K and greater than 200K when separated under nonreducing conditions. One of these antibodies showed no clear reactivity with the polypeptides, one detected a 58K and 92-94K species and one detected a 58K and 130K species, when separated under reducing conditions.