In vitro stimulation with glutamic acid decarboxylase (GAD65) leads to an oligoclonal response of peripheral T-cells in an IDDM patient.
The enzyme glutamic acid decarboxylase (GAD65) is a major autoantigen in insulin-dependent diabetes mellitus (IDDM). To study T-cell reactivity towards GAD, peripheral blood leucocytes from seven patients with IDDM and five control subjects were stimulated in vitro with recombinant GAD. All diabetics studied were heterozygous for diabetes-associated HLA alleles, i.e. HLA-DRB1*03,*04-DQB1 *0302,*0201. A single IDDM subject (no. GAD65.05) revealed a strong response against GAD65. After stimulation, his T-cell receptor beta (TCRBV) usage was found to be oligoclonal. The sequence analysis of the putative peptide binding region of the T-cell receptor (CDR3 region) of 37 GAD-reactive T-cell clones revealed no common CDR3 motif. The stimulation of GAD-reactive T-cells could be inhibited with anti-class II monoclonal antibodies, indicating a class II restricted T-cell response. In addition, GAD65-responsive T-cells revealed a Th1 cytokine response pattern. The author's data suggest that GAD-reactive T-cells of Th1 phenotype can be obtained after in vitro stimulation of peripheral blood leucocytes from an HLA-DRB1*03/*04 heterozygous IDDM patient. The lack of a common CDR3 motif suggests the absence of an immunodominant T-cell epitope in that patient, or may indicate receptor repertoire spreading of peripheral T-lymphocytes.
Weiss
U
U
Medizinische Klinik, Universität Ulm, Germany.
Manfras
B J
BJ
Terjung
D
D
Eiermann
T
T
Wölpl
A
A
Löliger
C
C
Kühnl
P
P
Boehm
B O
BO
D000595:Amino Acid Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D015329:Gene Rearrangement, T-Lymphocyte; D005968:Glutamate Decarboxylase / Q000378:metabolism*; D006801:Humans; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000096:biosynthesis / Q000235:genetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000276:immunology*
D008222:Lymphokines; D012333:RNA, Messenger; D011948:Receptors, Antigen, T-Cell; D015375:Receptors, Interleukin-2; D005968:Glutamate Decarboxylase