One of the major challenges facing HIV treatment and vaccine design is the virus' capacity to mutate extremely rapidly in response to a changing environment. The course of HIV infection within a given individual is characterized by a constant, dynamic evolution of the virus. It is now appreciated that a wide range of host genetic factors influences the course of HIV infection and disease progression. The proposed research project seeks to investigate the effects of genetic variation within specific genes of the human immune system (called the ""Major Histocompatibility Complex"" or ""MHC"" genes) on the clinical course of HIV infection. The results of this project will help us gain a more detailed understanding of the multiple genetic factors that affect the course of HIV infection, and help bring us closer to the potential incorporation of human genetic information into the clinical management and treatment of this disease. In addition, this research will be of relevance in the continuing efforts to develop a vaccine against HIV. Research such as this will help us develop and implement strategies for clinical management of HIV/AIDS and will therefore ultimately be of benefit to individuals living with HIV.