ANTIGENS LINKED TO SYNTHETIC MICROSPHERES INDUCE IMMUNE-RESPONSES IN PRIMATES IN THE ABSENCE OF ADJUVANT

Although most strategies of vaccination require immunopotentiation to induce efficient immune responses, the development of new adjuvants fo r human vaccines is highly limited by safety problems. In order to ove rcome this problem, we developed a new vaccine formulation based on th e covalent linkage of protein or peptide to synthetic microspheres. In previous experiments performed in mice, we demonstrated that these pa rticulate antigens induce strong antigen-specific CD4(+) T cell prolif erative responses in the absence of adjuvant. In the present study, we analyzed the immunogenicity in primate Saimiri sciureus monkeys of tw o different proteins linked to synthetic microspheres. Immune response s induced by these particulate proteins administered without adjuvant were compared to those stimulated by the soluble antigens injected wit h alum. We currently demonstrated that, in monkeys, particulate antige ns administered without adjuvant, induced good PBMC proliferative resp onse and antibody production. Furthermore, the analysis of antibody re sponses using mAbs specific for different Saimiri sciureus immunoglobu lins showed that the antibody response profiles were different in monk eys immunized with soluble versus particulate form of antigens. Result s of this study demonstrate that particulate form of antigen may stimu late qualitatively different immune responses as compared to alum and therefore suggest that this new antigen formulation could be an attrac tive candidate for the development of vaccines.