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APCs Present Aβk-Derived Peptides That Are Autoantigenic to Type B T Cells

2003; American Association of Immunologists; Volume: 170; Issue: 8 Linguagem: Inglês

10.4049/jimmunol.170.8.4155

1550-6606

Scott B. Lovitch, James J. Walters, Michael L. Gross, Emil R. Unanue,

Immune Cell Function and Interaction

Abstract Type B T cells recognize peptide provided exogenously but are ignorant of the same epitope derived from intracellular processing. In this study, we demonstrate the existence of type B T cells to an abundant autologous peptide derived from processing of the I-Ak β-chain. T cell hybridomas raised against this peptide fail to recognize syngeneic APC despite abundant presentation of the naturally processed epitope but react in a dose-dependent manner to exogenous peptide. Moreover, these hybridomas respond to Aβk peptide extracted from the surface of I-Ak-expressing APC. This peptide was isolated from B cell lines where it was found in high abundance; it was also present in lines lacking HLA-DM, but in considerably lower amounts. Therefore, type B T cells exist in the naive repertoire to abundant autologous peptides. We discuss the implications of these findings to the potential biological role of type B T cells in immune responses and autoimmune pathology.