title: Human vascular endothelial cells do not induce anergy in allogeneic CD4+ T cells unless costimulation is prevented.
abstract: Human vascular endothelial cells expressing MHC class II molecules have previously been shown to stimulate the proliferation of allogeneic CD4+ human T lymphocytes. Here we show that allogeneic CD4+ T cells from individual A (TA) respond to class II+ endothelial cells from individual B (EB) by inducing interleukin (IL)-2 mRNA, detectable by semiquantitative polymerase chain reaction, within 12 hr. Responding T cells (TA) that are harvested after 12 hr, rested for 3 days, and then re-exposed to the same class II+ EB stimulators can again respond by proliferation that is equivalent in degree to that observed with third-party class II+ endothelial cells (EC) as stimulators and a little greater than that observed in the primary responses. Incorporation of antibodies to LFA-3, an endothelial costimulatory molecule for T cells, or to both IL-2 and IL-2 receptor (R) during the first-round stimulation prevented the subsequent second-round proliferation of TA to class II+ EB but not to class II+ EC. This nonresponsiveness induced by anti-LFA-3 or anti-IL-2/IL-2R could be overcome by the incorporation of cyclosporine during the first-round stimulation or by incorporation of IL-2 during the second-round stimulation. These observations suggest that class II+ endothelial cells within allografts will not induce anergy in host CD4+ T cells unless costimulation is blocked or the ability of CD4+ T cells to respond by proliferation is prevented; even then the response may be modified by prevailing cyclosporine or IL-2 levels.
authors.affiliation: Centre for Clinical Research in Immunology and Signalling, Medical School, University of Birmingham, Edgbaston, United Kingdom.
authors.forename: C O
authors.initials: CO
authors.lastname: Savage
authors.forename: C J
authors.initials: CJ
authors.lastname: Brooks
mesh_terms: D000906:Antibodies / Q000494:pharmacology; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018968:CD58 Antigens / Q000276:immunology; D002450:Cell Communication / Q000502:physiology; D002478:Cells, Cultured; D017635:Clonal Anergy; D016572:Cyclosporine / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D007376:Interleukin-2 / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D000906:Antibodies; D018968:CD58 Antigens; D000949:Histocompatibility Antigens Class II; D007166:Immunosuppressive Agents; D007376:Interleukin-2; D012333:RNA, Messenger; D007371:Interferon-gamma; D016572:Cyclosporine