Candidate: Michael McChesney earned his M.D. from the University of Arizona in 1979 and received clinical training in internal medicine and rheumatology at the University of New Mexico. From 1984-88 he was a post doctoral fellow with Michael Oldstone in the Department of Immunology at the Scripps Clinic and Research Foundation working primarily on measles. From 1988-90 he was a Fogarty Fellow at the Institute Pasteur working on HIV. Since 1991 he has held his current position in the Department of Medical Pathology at the University of California at Davis where he is Assistant Adjunct Professor of Pathology. He has research support into 1997 to conduct studies on viral diseases in macaques and requests salary support in the present application. Career Development Plan - The plan is for Dr. McChesney to focus his research efforts on his long-term career interest in viral immunology and the pathogenesis of viral disease. The Department of Pathology views the candidate as a bridge between the Schools of Medicine and Veterinary Medicine through his research at the primate center. As an Adjunct Faculty member, the candidate must rely upon grants and contracts for salary support. Dr. McChesney also requires the funds from this grant to allow him to advance professionally at the University of California at Davis. With an award he will be freed, at least for a short time, from the requirement of writing grant proposals to support his research and he will be able to devote himself to his research and to some additional teaching. The latter is required to allow him to advance through the academic ranks. Dr. McChesney is supervising two Ph.D. candidates, he teaches medical students in an Introductory Pathology course and he is a member of the Comparative Pathology Graduate Group. Research Plan - The overall plan is to compare the pathogenesis of measles and SIV in rhesus macaques. These infections are being used as representative viral infections that result in virus clearance (measles) or virus persistence (SIV). The hypothesis is that the immune responses to these infections are different and determine outcome. Two alternative scenarios are proposed and will be tested: (1) CD8+ cytotoxic T cells control viral replication in both, but this response is insufficient in SIV infection; (2) antiviral delayed hypersensitivity (defined as CD4-induced-suppression of virus replication in macrophages) is not elicited by either virus, but if elicited, would result in immunopathology in measles and protection in SIV. Environmental and Institutional Commitment - The investigator is a member of the Pathology Department at the School of Medicine and as a Core Investigator has access to the virology and immunology facilities at the California Regional Primate Research Center. As a non tenure-track faculty member, his salary is not provided by the School and must be generated from research grants and contracts.