title: Immunoregulatory CD8+ cells recognize antigen-activated CD4+ cells in myasthenia gravis patients and in healthy controls.
abstract: CD8+ cells inhibiting the response of CD4+ cells exist in rodents, recognizing epitopes unique to a CD4+ clone (Ids) or expressed by all activated CD4+ cell (ergotypes). Stimulation of CD8+ cells recognizing ergotypes shared by all Ag-activated CD4+ cells would be useful for treatment of diseases involving undesirable CD4+ responses to ill defined Ags, such as many autoimmune diseases and allergies. As a first step toward demonstrating the existence of anti-ergotype CD8+ immunoregulatory cells in humans, we investigated here whether CD8+ cells recognizing Ag-activated CD4+ cells exist in autoimmune and healthy humans. CD4+ cells specific for human muscle acetylcholine receptor, tetanus, or diphtheria toxoids were propagated from patients with myasthenia gravis patients and healthy controls. Ag-activated CD4+ cells were irradiated and used as Ag to test the response of CD(4+)-depleted CD(8+)-enriched PBMC (CD8+ PBMC) from myasthenic patients and controls and to propagate short-term CD8+ cell lines from CD8+ PBMC. In both patients and controls CD8+ PBMC and CD8+ lines responded vigorously to autologous Ag-activated CD4+ cells. The CD8+ lines responded equally well to the Ag-activated CD4+ cells of different Ag specificity, suggesting that they recognized CD4+ ergotypes. They did not seem to respond to CD4+ cells activated by PHA. The CD8+ cells recognized class I-restricted epitopes, as their response to activated CD4+ cells was suppressed by anti-class I Ab. CD8+ cells recognizing Ag-activated CD4+ were present cells in the controls for 5 to 12 wk after immunization. In myasthenic patients, CD8+ cells recognizing activated anti-acetylcholine receptor CD4+ cells seemed to be always present.
authors.affiliation: Department of Pharmacology, University of Minnesota, Minneapolis 55455.
authors.forename: M H
authors.initials: MH
authors.lastname: Yuen
authors.forename: M P
authors.initials: MP
authors.lastname: Protti
authors.forename: B
authors.initials: B
authors.lastname: Diethelm-Okita
authors.forename: L
authors.initials: L
authors.lastname: Moiola
authors.forename: J F
authors.initials: JF
authors.lastname: Howard
authors.forename: B M
authors.initials: BM
authors.lastname: Conti-Fine
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000941:Antigens / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D004168:Diphtheria Toxoid / Q000276:immunology; D000939:Epitopes / Q000276:immunology; D005260:Female; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000276:immunology*; D010455:Peptides / Q000276:immunology; D010835:Phytohemagglutinins / Q000276:immunology; D011950:Receptors, Cholinergic / Q000276:immunology; D013745:Tetanus Toxoid / Q000276:immunology
chemical_list: D000941:Antigens; D004168:Diphtheria Toxoid; D000939:Epitopes; D015395:Histocompatibility Antigens Class I; D010455:Peptides; D010835:Phytohemagglutinins; D011950:Receptors, Cholinergic; D013745:Tetanus Toxoid