The involvement of CXCR4 and CCR5 coreceptors in apoptosis induced by the HIV envelope (Env) proteins has not been well defined. We found that simian human immunodeficiency virus (SHIV) virus-like particles (VLPs) containing HIV Env proteins preferentially induce apoptosis of cells corresponding to their coreceptor usage in a CD4+ T cell line. We also demonstrated that induction of apoptosis by SHIV VLPs is correlated with coreceptor usage in a non-T cell line. We examined the effects of SHIV VLPs containing Env proteins derived from either a T-cell-tropic HIV (BH10) strain or a dual-tropic HIV (89.6) strain on induction of apoptosis in recombinant CD4+ human osteosarcoma (HOS) cells expressing either CXCR4 (HOS-CD4.CXCR4) or CCR5 coreceptors (HOS-CD4.CCR5). HOS-CD4.CXCR4 or HOS-CD4.CCR5 cells were activated with concanavalin A and cocultured with VLPs. By TUNEL (TdT-mediated dUTP-X nick end labeling) fluorescence staining and flow cytometry assays, SHIV BH10 VLPs were found to preferentially induce apoptosis in HOS-CD4.CXCR4 cells but not in HOS-CD4 or HOS-CD4.CCR5 cells. On the other hand, SHIV 89.6 VLPs induced an elevated level of apoptosis in both HOS-CD4.CXCR4 and HOS-CD4.CCR5 cells in a dose-dependent fashion. These data demonstrate that T-cell-tropic BH10 Env preferentially utilizes CXCR4, but not CCR5, for induction of apoptosis, whereas dual-tropic 89.6 Env induces apoptosis in both CXCR4- and CCR5-containing cell lines.
Copyright 2001 Academic Press.