This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Cytomegalovirus (CMV) is an important opportunistic pathogen in AIDS. Although CMV disease manifests in the setting of immunosuppression, the mechanisms underlying impaired CMV-specific T cell immunity in AIDS are not well understood. To determine whether loss of CD4-positive T cells can impair functionality of CMV-specific CD8-positive T cells, we are investigating CMV reactivation in rhesus macaques following in vivo antibody-mediated CD4+ and CD8+ T lymphocyte depletion.