Proliferating and helper T lymphocytes display distinct fine specificities in response to human fibrinopeptide B.
The fine specificity of T cell responses involved in the generation of help for antibody production and proliferation was examined by using the 14 amino acid peptide human fibrinopeptide B (hFPB, B beta 1-14) and its synthetic peptide homologues B beta 1-14(Lys14), B beta 1-13, and B beta 3-14. Peritoneal exudate or lymph node T cells from C57BL/10 and B10.BR mice immunized with hFPB or its synthetic homologues were used to measure in vitro proliferative responses. T cells from hFPB-immunized B10.BR mice showed specific proliferation to hFPB, but were unresponsive to B beta 1-14(Lys14), B beta 1-13, and B beta 3-14. B10.BR mice immunized with B beta 1-14(Lys14), B beta 1-13, or B beta 3-14 were unresponsive to all peptides tested. T cells from C57BL/10 mice showed no specific proliferation after immunization and challenge with any of the peptide antigens. In contrast to the patterns of T cell proliferation, immunization of both B10.BR and C57BL/10 mice with hFPB, B beta 1-14(Lys14), B beta 1-13, or B beta 3-14 primed for significant helper T cell activity, as assessed by the augmentation of a primary in vitro B cell IgM anti-FITC plaque-forming cell response after culture with B beta 1-1(Lys14)-FITC. Significant peptide-specific helper activity was observed when the FITC moiety was conjugated to the carboxyl terminal lysine (B beta 1-14(Lys14)-FITC) as well as FITC substitution at the amino terminus (FITC-B beta 3-13 or FITC-B beta 3-14). These results suggest that the fine specificity of T cell responses to peptide antigens are different for helper and proliferating T cells and that responsiveness by one T cell subpopulation does not predict the response pattern of other functional subpopulations.
D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology; D000939:Epitopes / Q000032:analysis*; D005340:Fibrinogen / Q000276:immunology*; D005345:Fibrinopeptide B / Q000276:immunology*; D006462:Hemolytic Plaque Technique; D006801:Humans; D007108:Immune Tolerance; D007075:Immunoglobulin M / Q000096:biosynthesis; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D000939:Epitopes; D007075:Immunoglobulin M; D005345:Fibrinopeptide B; D005340:Fibrinogen