Ia-independent binding of peptide antigen to the T cell receptor.
We have investigated the potential for direct interaction between a peptide Ag, human fibrinopeptide B (hFPB), and the TCR on an hFPB-specific murine T hybridoma. Fluoresceinated hFPB binds specifically to hFPB-responsive T cells, but not to unrelated T hybrids. Among variant subclones of the original hybridoma, ability to bind hFPB correlates with hFPB-specific response and expression of the CD3/TCR complex, indicating that hFPB is binding to the TCR. This TCR-hFPB interaction has an affinity of approximately 6.6 microM, reflecting slow association and rapid dissociation of the Ag from its receptor. These findings confirm the potential for direct Ag-TCR interaction and indicate an Ag recognition mechanism that is not initiated by Ag-MHC interaction.
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Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109.
Thomas
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D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D017252:CD3 Complex; D002460:Cell Line; D005345:Fibrinopeptide B / Q000276:immunology* / Q000378:metabolism; D005434:Flow Cytometry; D000949:Histocompatibility Antigens Class II / Q000502:physiology*; D006825:Hybridomas; D066298:In Vitro Techniques; D007700:Kinetics; D051379:Mice; D011485:Protein Binding; D011948:Receptors, Antigen, T-Cell / Q000032:analysis / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D000949:Histocompatibility Antigens Class II; D011948:Receptors, Antigen, T-Cell; D005345:Fibrinopeptide B