Autoantibodies and associated T-cell responses to determinants within the 831-860 region of the autoantigen IA-2 in Type 1 diabetes.
B-cells influence T-cell reactivity by facilitating antigen presentation, but the role of autoantibody-secreting B-cells in regulating T-cell responses in Type 1 diabetes is poorly defined. The aims of this study were to characterise epitopes on the IA-2 autoantigen for three monoclonal antibodies from diabetic patients by amino acid substitutions of selected residues of IA-2, establish contributions of these epitopes to binding of serum antibodies in Type 1 diabetes and relate B- and T-cell responses to overlapping determinants on IA-2. The monoclonal antibodies recognised overlapping epitopes, with residues within the 831-860 region of IA-2 contributing to binding; substitution of Glu836 inhibited binding of all three antibodies. Monoclonal antibody Fab fragments and substitution of residues within the 831-836 region blocked serum antibody binding to an IA-2 643-937 construct. IL-10-secreting T-cells responding to peptides within the 831-860 region were detected by cytokine-specific ELISPOT in diabetic patients and responses to 841-860 peptide were associated with antibodies to the region of IA-2 recognised by the monoclonal antibodies. The study identifies a region of IA-2 frequently recognised by antibodies in Type 1 diabetes and demonstrates that these responses are associated with T-cells secreting IL-10 in response to a neighbouring determinant.
Weenink
S M
SM
Diabetes Research Group, Division of Reproduction & Endocrinology, 2nd Floor Hodgkin Building, King's College London, Guy's Campus, London, United Kingdom.
Lo
J
J
Stephenson
C R
CR
McKinney
P A
PA
Ananieva-Jordanova
R
R
Rees Smith
B
B
Furmaniak
J
J
Tremble
J M
JM
Bodansky
H J
HJ
Christie
M R
MR
D000293:Adolescent; D000328:Adult; D019943:Amino Acid Substitution; D000911:Antibodies, Monoclonal / Q000276:immunology; D001323:Autoantibodies / Q000276:immunology*; D001324:Autoantigens / Q000276:immunology*; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000235:genetics / Q000276:immunology*; D005260:Female; D006801:Humans; D007223:Infant; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D016753:Interleukin-10 / Q000096:biosynthesis / Q000276:immunology; D008297:Male; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8 / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D055815:Young Adult
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D001324:Autoantigens; D018984:Epitopes, T-Lymphocyte; C096322:ICA512 autoantibody; C508609:IL10 protein, human; D016753:Interleukin-10; D007371:Interferon-gamma; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8