CD4⁺ and CD8⁺ T cell death during human immunodeficiency virus infection in vitro

We have evaluated the death of CD4− and CD8+ T cells during in vitro human immunodeficiency virus (HIV) infection of peripheral blood mononuclear cells (PBMC) and tonsilar tissue. Acute infections with several X4 and R5 HIV isolates induced a decrease in cell viability that was higher in infections with X4 viruses and correlated with an increased rate of CD4+ T-cell death. In CD4+ T cells, the primary X4 isolate AOM induced higher levels of death than the laboratory X4 isolates IIIB and NL4-3 or the R5 isolates BaL and MDM. An effect on CD8+ T-cell viability was exclusively observed in infections by X4 viruses, including the NL4-3 strain, in both PBMC and tonsilar tissue. This effect was dependent on the env gene of the infecting isolate and required productive HIV replication in CD4+ but not in CD8+ T cells. Our results suggest that X4 and R5 HIV isolates depleted CD4+ T cells to a different extent and that CD8+ T-cell viability may also be affected by mechanisms other than those acting in CD4+ T cells. © 2001 Academic Press.