title: T cell-derived suppressive activity: evidence of autocrine noncytolytic control of HIV type 1 transcription and replication.
abstract: The ability of CD8+ T lymphocytes to suppress the transcription and replication of HIV-1 is well documented. We have demonstrated that the factor(s) responsible for the suppression of HIV-1 LTR-mediated gene expression are not the CC chemokines RANTES, MIP-1alpha, and MIP-1beta. Interestingly, these and other chemokines and cytokines are produced by both CD8+ and CD4+ T lymphocytes. On the presumption that CD4+ T lymphocytes may also be able to modulate HIV-1 expression in vitro we assessed the LTR-modulatory effects of a panel of culture supernatants derived from stimulated CD4+ T lymphocytes from HIV-positive patients and uninfected controls. Supernatants of both CD4+ and CD8+ T cells mediated a suppression of LTR-driven gene expression in Jurkat T cells and an enhancement of gene expression in U38 monocytic cells. On the basis of these results, and using a herpesvirus saimiri (HVS)-transformed CD4+ T lymphocyte clone (HVSCD4), we demonstrate that both suppressive and enhancing effects are dose dependent. Furthermore, we have shown that supernatants of both HVSCD4 and HVSCD8 cells suppress LTR-mediated gene expression and HIV-1 replication in transfected/infected T cells. In U1 monocytic cells, supernatants of both CD4+ and CD8+ lymphocytes from an HIV-1-infected individual enhanced LTR-mediated gene expression, HIV-1 replication, and TNF-alpha production. However, only these effects as induced by CD8+ T cells were sensitive to the G protein inhibitor pertussis toxin. These results indicate that factors produced by both CD4+ and CD8+ T cells exert dichotomous effects on HIV-1 gene expression and replication in T cells and monocytes.
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster University Health Sciences Centre, Hamilton, Ontario, Canada.
authors.forename: J G
authors.initials: JG
authors.lastname: Leith
authors.forename: K F
authors.initials: KF
authors.lastname: Copeland
authors.forename: P J
authors.initials: PJ
authors.lastname: McKay
authors.forename: D
authors.initials: D
authors.lastname: Bienzle
authors.forename: C D
authors.initials: CD
authors.lastname: Richards
authors.forename: K L
authors.initials: KL
authors.lastname: Rosenthal
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000502:physiology*; D018414:CD8-Positive T-Lymphocytes / Q000502:physiology; D002460:Cell Line; D002472:Cell Transformation, Viral; D017077:Culture Media, Conditioned; D004306:Dose-Response Relationship, Immunologic; D015967:Gene Expression Regulation, Viral; D016325:HIV Long Terminal Repeat / Q000235:genetics*; D015497:HIV-1 / Q000502:physiology*; D006567:Herpesvirus 2, Saimiriine; D006801:Humans; D019169:Jurkat Cells; D008222:Lymphokines / Q000502:physiology*; D009000:Monocytes / Q000821:virology; D037342:Pertussis Toxin; D014158:Transcription, Genetic; D020298:U937 Cells; D010566:Virulence Factors, Bordetella; D014779:Virus Replication
chemical_list: D017077:Culture Media, Conditioned; D008222:Lymphokines; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin