RAPID SCREENING FOR MAMU-A1-POSITIVE RHESUS MACAQUES USING A SIVMAC GAG PEPTIDE-SPECIFIC CYTOTOXIC T-LYMPHOCYTE ASSAY

As part of an ongoing vaccine study using peptide immunogens designed to stimulate simian immunodeficiency virus (SIV)mac-specific cytotoxic T lymphocytes (CTL) it was necessary to identify rhesus macaques with in our colony bearing the Mamu-A1 major histocompatibility complex (MH C) class I haplotype. Peripheral blood mononuclear cells (PBMC) from i ndividual monkeys were analysed by immunoelectrofocusing for the prese nce of a band corresponding to the Mamu-A1 molecule. In addition, PBMC were pulsed with the SIVmac Gag peptide 11 (against which CTL are Mam u-A1 restricted) and analysed for susceptibility to lysis by peptide 1 1-specific CTL. PBMC from all of the rhesus macaques shown to be Mamu- A1 positive by immunoelectrofocusing were highly sensitive to lysis by the peptide 11-specific CTL. A total of 46% (16 from 35) of the rhesu s macaques originating from India were found to be Mamu-A1 positive, w hereas none of the Chinese rhesus (0 from 37) macaques possessed this haplotype. Once a peptide-specific CTL is established, screening by CT L assay offers a faster, reliable and more relevant alternative to imm unoelectrofocusing for selecting monkeys for use in vaccination trials .