Characterization of self-glutamic acid decarboxylase 65-reactive CD4+ T-cell clones established from Japanese patients with insulin-dependent diabetes mellitus.
To investigate autoimmunity to glutamic acid decarboxylase (GAD) 65 in Japanese patients with insulin-dependent diabetes mellitus (IDDM, type I diabetes), we established seven CD4+ T-cell clones, by stimulating peripheral blood mononuclear cells (PBMC) of six IDDM patients, using a mixture of overlapping human GAD65 peptides. No GAD65 autoreactive T-cell clones were evidenced in four healthy controls. Specificities of T-cell clones were as follows: (a) two clones specific to GAD65 p111-131 (residue 111 to 131) + DR53 (DRB4*0103); (b) one clone specific to GAD65 p413-433 + DR1 (DRB1*0101); (c) two clones specific to GAD65 p200-217 + either DR9 (DRB1*0901) or DR8 (DRB1*0802); and (d) two clones specific to GAD65 p368-388 + DP2 (DPA1*01 or 0201-DPB1*0201). Two DR53-restricted and one DR1-restricted T-cell clones, responded to a recombinant human GAD65 protein, and showed cytotoxicity against B lymphoblastoid cell lines pre-pulsed with the peptides. Six T-cell clones exhibited the Th1-like phenotype. Interestingly, two DR53-restricted T-cell clones killed a Fas-deficient B lymphoblastoid cell line, thereby indicating that cytotoxicity was not completely dependent on a Fas-Fas ligand interaction. Thus, the T-cell epitopes were mapped in a limited portion of GAD65 protein, with a tendency to be restricted by disease-associated HLA-DR, but not DQ molecules.
Department of Neuroscience and Immunology, Kumamoto University Graduate School of Medical Sciences, Japan.
H
H
Tabata
T
T
Kanai
H
H
Yoshizumi
S
S
Nishiyama
S
S
Fujimoto
I
I
Matsuda
M
M
Yasukawa
S
S
Matsushita
Y
Y
Nishimura
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D015551:Autoimmunity; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002648:Child; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D003922:Diabetes Mellitus, Type 1 / Q000201:enzymology / Q000276:immunology*; D005260:Female; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000276:immunology*; D006680:HLA Antigens / Q000276:immunology; D006801:Humans; D007564:Japan; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology
D006680:HLA Antigens; D010446:Peptide Fragments; D011994:Recombinant Proteins; D005968:Glutamate Decarboxylase