THE ROLE OF MAJOR HISTOCOMPATIBILITY COMPLEX POLYMORPHISMS ON SIV INFECTION IN RHESUS MACAQUES

To investigate whether Major Histocompatibilty Complex (MHC) polymorph isms influence either susceptibility to SIV infection or progress to a ctual disease, rhesus monkeys were subjected to various forms of SIV i nfection and screened for allelic MHC heterogeneity by means of serolo gical and biochemical methods. Animals that are protected against cell associated virus challenges were those that are SIV vaccinated and wh ich shared a particular MHC class I allele (Mamu-A26) with the donor o f the infected cells. Comparisons on the rate of infection to AIDS in SIV,,, infected macaques showed that most Mamu-A26 positive animals be long to the group of long time survivors. In our outbred colony, about 25% of the rhesus macaques are positive for the Mamu-A26 serotype. Ge l electrophoretic analyses demonstrated that isoelectric point (pi) di fferences of MHC class I heavy chains correlate with allotyping. In ad dition, the Mamu-A26 specificity was found to display heterogeneity. T hese results suggest that particular Mamu-A26 (associated) gene produc ts may have the capacity or quality to induce antigen specific cytotox ic T lymphocyte responses that play a key role in controlling SIV infe ction or vaccine protection.