title: Characterization of a human T cell line reactive to a 52 kDa islet protein.
abstract: A 52 kDa islet protein has recently been identified as the target of autoantibodies in the NOD mouse model of IDDM and humans with IDDM. However, the presence of T cell immunity against the 52 kDa islet protein in IDDM has not been reported. We report the establishment and characterization of a T cell line (19KW) that reacts to purified 52 kDa islet protein (purified p52) from a subject with IDDM. The purified p52 induced a proliferative response as measured by thymidine incorporation in the 19KW T cell line with a stimulating index of up to 48. The proliferative responses were greater with increasing doses of purified p52 (0.1, 0.5, 2.0, and 6.0 microg/well). No reactivity was found to a liver fraction purified in the same manner as 52 kDa protein, BSA, ovalbumin, extracts of rat muscle, fibroblast, adrenal, or pituitary tissue and to a rat exocrine cell tumor. Irradiated PBMC were required as antigen presenting cells (APC) for 19KW reactivity to the purified p52. The addition of anti-HLA DR or anti-HLA DQ antibodies significantly decreased the islet antigen-induced proliferative response. The addition of antibodies to HLA DP and class I MHC had no effect. Flow cytometric analysis revealed that the majority of T cells expressed CD4 and CD45RO molecules. T cell receptors Vbeta6 and Vbeta5.1 were found on 30 and 14% of the CD3+ (T cells) 19KW cells, respectively. In conclusion, a purified p52-reactive human T cell line predominantly consisting of TCR Vbeta6+ and Vbeta5.1+ cells has been established from a subject with IDDM. Reactivity to the purified p52 is antigen dose-dependent, tissue specific, requires irradiated PBMC as antigen presenting cells, and is HLA DR- and HLA DQ-restricted. T cell lines specifically reactive to p52 may be useful for investigating further the role of this antigen in the pathogenesis of IDDM.
authors.affiliation: Department of Pediatrics and Lombardi Cancer Center, Georgetown University School of Medicine, Washington, DC 20007-2197, USA.
authors.forename: D O
authors.initials: DO
authors.lastname: Sobel
authors.forename: T
authors.initials: T
authors.lastname: Fleisher
authors.forename: D G
authors.initials: DG
authors.lastname: Karounos
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D001324:Autoantigens / Q000737:chemistry*; D002460:Cell Line; D003922:Diabetes Mellitus, Type 1 / Q000209:etiology / Q000276:immunology; D006683:HLA-DQ Antigens / Q000378:metabolism; D006684:HLA-DR Antigens / Q000378:metabolism; D006801:Humans; D007111:Immunity, Cellular; D007515:Islets of Langerhans / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008970:Molecular Weight; D011506:Proteins / Q000737:chemistry / Q000276:immunology*; D051381:Rats; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D001324:Autoantigens; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D011506:Proteins