Establishment of T cell lines to bovine beta-casein and beta-casein-derived epitopes in patients with type 1 diabetes.
Enhanced cellular immune response to bovine beta-casein has been reported in patients with type 1 diabetes. In this study we aimed to establish beta-casein-specific T cell lines from newly diagnosed type 1 diabetic patients and to characterise these cell lines in terms of phenotype and epitope specificity. Furthermore, since sequence homologies exist between beta-casein and putative beta-cell autoantigens, reactivity to the latter was also investigated. T cell lines were generated from the peripheral blood of nine recent onset type 1 diabetic patients with different HLA-DQ and -DR genotypes, after stimulation with antigen pulsed autologous irradiated antigen presenting cells (APCs) and recombinant human interleukin-2 (rhIL-2). T cell line reactivity was evaluated in response to bovine beta-casein, to 18 overlapping peptides encompassing the whole sequence of beta-casein and to beta-cell antigens, including the human insulinoma cell line, CM, and a peptide from the beta-cell glucose transporter, GLUT-2. T cell lines specific to beta-casein could not be isolated from HLA-matched and -unmatched control subjects. beta-Casein T cell lines reacted to different sequences of the protein, however a higher frequency of T cell reactivity was observed towards the C-terminal portion (peptides B05-14, and B05-17 in 5/9 and 4/9 T cell lines respectively). Furthermore, we found that 1 out of 9 beta-casein-specific T cell lines reacted also to the homologous peptide from GLUT-2, and that 3 out of 4 of tested cell lines reacted also to extracts of the human insulinoma cell line, CM. We conclude that T cell lines specific to bovine beta-casein can be isolated from the peripheral blood of patients with type 1 diabetes; these cell lines react with multiple and different sequences of the protein particularly towards the C-terminal portion. In addition, reactivity of beta-casein T cell lines to human insulinoma extracts and GLUT-2 peptide was detected, suggesting that the potential cross-reactivity with beta-cell antigens deserves further investigation.
Monetini
L
L
Department of Endocrinology and Diabetes, University 'Campus Biomedico', Rome, Italy.
Barone
F
F
Stefanini
L
L
Petrone
A
A
Walk
T
T
Jung
G
G
Thorpe
R
R
Pozzilli
P
P
Cavallo
M G
MG
D000293:Adolescent; D000818:Animals; D001324:Autoantigens / Q000276:immunology; D016022:Case-Control Studies; D002364:Caseins / Q000276:immunology*; D002417:Cattle; D018929:Cell Culture Techniques; D002460:Cell Line; D002648:Child; D003429:Cross Reactions; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D005260:Female; D005838:Genotype; D051273:Glucose Transporter Type 2; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D006650:Histocompatibility Testing; D006801:Humans; D016130:Immunophenotyping; D007340:Insulinoma; D007371:Interferon-gamma / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D007515:Islets of Langerhans / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014407:Tumor Cells, Cultured
D001324:Autoantigens; D002364:Caseins; D000939:Epitopes; D051273:Glucose Transporter Type 2; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D009004:Monosaccharide Transport Proteins; D015847:Interleukin-4; D007371:Interferon-gamma