A commonly recognized simian immunodeficiency virus Nef epitope presented to cytotoxic T lymphocytes of Indian-origin rhesus monkeys by the prevalentmajor histocompatibility complex class I allele Mamu-A*02

The ability to monitor vaccine-elicited CD8(+) cytotoxic T-lymphocyte (CTL) responses in simian immunodeficiency virus (SIV) and simian-human immunode ficiency virus (SHIV)-infected rhesus monkeys has been limited by our knowl edge of viral epitopes predictably presented to those lymphocytes by common rhesus monkey MHC class I alleles. We now define an SIV and SHIV Nef CTL e pitope (YTSGPGIRY) that is presented to CD8(+) T lymphocytes by the common rhesus monkey MHC class I molecule Mamu-A*02. All seven infected Alamu-A*02 (+) monkeys evaluated demonstrated this response, and peptide-stimulated in terferon gamma Elispot assays indicated that the response represents a larg e proportion of the entire CD8+ T-lymphocyte SIV or SHIV-specific immune re sponse of these animals. Knowledge of this epitope and MHC class I allele s ubstantially increases the number of available rhesus monkeys that can be u sed for testing prototype HIV vaccines in this important animal model.