CHARACTERIZATION OF T CELL EPITOPES ON THE ENVELOPE GLYCOPROTEIN OF SIMIAN RETROVIRUS 1 AND 2 (SRV-1 AND SRV-2) IN SEVERAL MOUSE STRAINS*

Abstract Various mouse strains were immunized with either SRV-1 or SRV-2 virus adsorbed on alum. Seven to 14 days later spleen cells were removed, and spleen cells were cultured with varying amounts of SRV-1 virus and SRV-2 virus, or varying amounts of selected SRV-1 and SRV-2 synthetic envelope peptides to determine their ability to initiate T cell proliferative responses. Our studies demonstrated that all mouse strains tested gave strong proliferative responses with SRV-2 virus. In contrast, SRV-1 virus induced T cell proliferative responses only in H-2 k mouse strains. This apparent major histocompatibility complex (MHC)-restriction of SRV-1 virus-induced T cell proliferation correlates with the increased pathogenicity of SRV-1 virus in rhesus monkeys. The SRV envelope peptide 233–249 which is shared by both SRV-1 and SRV-2 virus initiates strong proliferative responses in both SRV-1 and SRV-2 virus immunized mice. The SRV-2 envelope peptide 96–102 initiates significant proliferative responses in SRV-2 immunized mice, and constitutes both a T and B cell epitope. The SRV-2 envelope peptide 127–152 has a 70% homology with the C -terminal region of SRV-1 peptide 142–167. The ability of SRV-2 peptide 127–152 to initiate T cell proliferation in SRV-1 virus immunized mice and the failure of the SRV-1 peptide 142–162 to initiate proliferation suggests that the region encompassing residues 160–167 must represent a T cell epitope in mice immunized with SRV-1 virus.