Identification of Novel HLA-A*0201-restricted epitopes in recent-onset type 1 diabetic subjects and antibody-positive relatives.
Cytotoxic T-lymphocytes (CTLs) are considered to be essential for beta-cell destruction in type 1 diabetes. However, few islet-associated peptides have been demonstrated to activate autoreactive CTLs from type 1 diabetic subjects. In an effort to identify novel epitopes, we used matrix-assisted algorithms to predict peptides of glial fibrillary acidic protein (GFAP), prepro-islet amyloid polypeptide (ppIAPP), and islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) that likely bind to HLA-A*0201 with a strong affinity and contain a COOH-terminal proteasomal cleavage site. Seven peptides stabilized HLA-A*0201 expression in binding assays and were used to stimulate peripheral blood mononuclear cells and were evaluated for granzyme B secretion. We found that 5 of 13 type 1 diabetic subjects and 4 of 6 antibody-positive relatives exhibited greater numbers of granzyme B-secreting cells in response to at least one putative epitope compared with healthy control subjects. The most prevalent responses in antibody-positive and type 1 diabetic subjects were to ppIAPP(9-17). Other peptides recognized by type 1 diabetic or antibody-positive subjects included GFAP(143-151), IGRP(152-160), and GFAP(214-222). These data implicate peptides of ppIAPP, GFAP, and IGRP as CTL epitopes for a heterogenous CD8(+) T-cell response in type 1 subjects and antibody-positive relatives.
Standifer
Nathan E
NE
Benaroya Research Institute at Virginia Mason, 1201 Ninth Ave., Room 260, Seattle WA, 98101, USA. nstand@benaroyaresearch.org
Ouyang
Qin
Q
Panagiotopoulos
Constadina
C
Verchere
C Bruce
CB
Tan
Rusung
R
Greenbaum
Carla J
CJ
Pihoker
Catherine
C
Nepom
Gerald T
GT
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000276:immunology*; D000939:Epitopes / Q000235:genetics; D005190:Family; D015234:HLA-A Antigens / Q000235:genetics*; D015789:HLA-A2 Antigen; D006801:Humans; D051379:Mice; D016688:Mice, Inbred NOD; D008875:Middle Aged; D010446:Peptide Fragments / Q000737:chemistry; D012016:Reference Values; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
D001323:Autoantibodies; D000939:Epitopes; D015234:HLA-A Antigens; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; D010446:Peptide Fragments