DIFFERENCES IN THE B-CELL AND T-CELL IMMUNE-RESPONSE TO THE ENVELOPE GLYCOPROTEIN-130 (GP130) OF THE MACAQUE STRAIN OF SIMIAN IMMUNODEFICIENCY VIRUS (SIV(MAC)), INDUCED BY IMMUNIZATION OF RHESUS MACAQUES WITH VIRUS-DERIVED OR VACCINIA VIRUS-EXPRESSED GP130

Rhesus macaques were immunized with purified virus-derived simian immu nodeficiency virus of macaques (SIV(mac)) 251/32H glycoprotein 130 (gp 130) or primed with recombinant vaccinia virus (VV) expressing the env gene of the SIV(mac) BK28 clone and boosted subsequently with virus-d erived gp130. High antibody titres of at least 10(4) against recombina nt gp140 were induced with both vaccines. Analysis of the antibody spe cificity with a peptide ELISA revealed that different linear epitopes were recognized after administration of virus-derived gp130 compared w ith those after priming with W. Antibodies to some epitopes (peptides 10 and 49), which were also found in SIV-infected animals, were induce d with both vaccines, whereas antibodies to other regions were induced by only one vaccine preparation. The analysis of the helper T cell re sponse revealed a poor immunogenicity of the virus-derived gp130, wher eas priming with VV induced a considerable helper T cell activity in a ll three vaccinees after the second VV infection. Using synthetic pept ides, several epitopes were identified. Our observations show that imm unization with a virus-derived gp130 or live recombinant VV induces a considerably different antibody and helper T cell response. These diff erences in immunogenicity might have important implications for furthe r vaccine development.