title: Characterization of the cytotoxic factor(s) released from thymic dendritic cells upon human immunodeficiency virus type 1 infection.
abstract: We previously demonstrated that infection of primary human thymic dendritic cells (DCs) with laboratory strains of HIV leads to the release of soluble factor(s) which induced thymocyte killing. In the present paper, we extend the characterization of this process. Our results reveal that primary HIV-1 isolates are similarly able to induce the production of cytotoxic factor(s) from thymic DCs and that the release of such factor(s) is dependent on viral infection. Interestingly, we observed that CD4+ and CD8+ purified thymocyte subsets, and activated PBMCs are susceptible to the cytotoxic activity, whereas freshly isolated resting PBMCs are resistant to this effect. Cycloheximide treatment prevents the killing of thymocytes exposed to HIV-infected DC supernatant, revealing that this form of cell death is an active biological process requiring protein synthesis. Finally, our data suggest that FasL and TNF alpha could both participate in the killing process. These in vitro observations provide a plausible model, whereby HIV-infected DCs can play a role in vivo in the induction of uninfected thymocyte killing.
authors.affiliation: Département de Microbiologie et Immunologie, Université de Montréal, Succursale Centre-ville, Québec, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Beaulieu
authors.forename: M
authors.initials: M
authors.lastname: Lafontaine
authors.forename: M
authors.initials: M
authors.lastname: Richer
authors.forename: I
authors.initials: I
authors.lastname: Courchesne
authors.forename: E A
authors.initials: EA
authors.lastname: Cohen
authors.forename: D
authors.initials: D
authors.lastname: Bergeron
mesh_terms: D000818:Animals; D017209:Apoptosis; D002453:Cell Cycle; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D017077:Culture Media, Conditioned; D003513:Cycloheximide / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic; D053938:DNA Fragmentation; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism / Q000821:virology*; D015497:HIV-1 / Q000276:immunology* / Q000502:physiology; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D055646:Killer Factors, Yeast; D051379:Mice; D014176:Protein Biosynthesis; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011506:Proteins / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology; D014771:Virion; D019014:fas Receptor / Q000276:immunology
chemical_list: D017077:Culture Media, Conditioned; D006684:HLA-DR Antigens; D055646:Killer Factors, Yeast; D011500:Protein Synthesis Inhibitors; D011506:Proteins; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor; D003513:Cycloheximide