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Insulin B chain functions as an effective competitor of antigen presentation via peptide homologies present in the

G G Miller1, J F Hoy, J W Thomas

  • 1Department of Medicine, Baylor College of Medicine, Houston, Texas 77030.

The Journal of Experimental Medicine
|June 1, 1989
PubMed

The B chain of mammalian insulins contains appropriately spaced amino acids that predict recognition by T cells. However, all T cell clones from an HLA-DR1, Dw6 diabetic donor recognize epitopes associated with the A chain, and the B chain was found to inhibit these responses. Effective intramolecular competition at the level of the APC, not a direct effect on the T cell, is responsible for the inhibition. Insulin B chain contains two clusters of amino acid homology with the TCR beta chain and B chain peptides lacking these clusters do not compete for antigen presentation. A hole in the repertoire for T cells that recognize this portion of the insulin molecule may arise in the thymus by deletion of T cells that recognize similar peptides.

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