T lymphocyte recognition of insolubilized peptide antigen.
To study the role of antigen-presenting cells (APC) in T lymphocyte responses, the stimulation requirements of a murine T cell hybridoma specific for the peptide antigen human fibrinopeptide B (hFPB)/I-Ak was examined. The fine specificity of T cell recognition of this peptide was determined by using several hFPB homologs and analogs, which indicated that the intact 14-amino acid peptide must remain intact to preserve the antigenic determinant, and that the carboxyl terminal Arg14 was important for T cell responses. Of particular interest was the finding that APC-associated hFPB failed to stimulate the T cells, and that activation was only observed with soluble peptide or by brief hFPB treatment of the T cells and APC mixed together. In addition, hFPB covalently bound to agarose beads was able to cause T cell activation, provided that I-Ak+ APC were also present in the culture. A number of control experiments were performed that showed that hFPB was not released from the bead and that the antigenic peptide involved in T cell responses remained bound to the beads. These results indicate that the form of the hFPB peptide antigen recognized by this T cell can be provided separately from APC.
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D000939:Epitopes; D005345:Fibrinopeptide B / Q000276:immunology; D005802:Genes, MHC Class II; D006825:Hybridomas; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D051379:Mice; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D012995:Solubility; D013601:T-Lymphocytes / Q000276:immunology*
D000939:Epitopes; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D005345:Fibrinopeptide B