title: T cell regulation of immunoglobulin class expression in the B cell response to TNP-Ficoll: characterization of the T cell responsible for preferential enhancement of the IgG2a response.
abstract: Syngeneic T cells injected into athymic nu/nu mice cause a preferential enhancement in the amount of IgG2a anti-TNP Ab produced by these mice to TNP-Ficoll. This enhancement appears to be caused by T cell effects on the IgG switching pathway. Through the use of F1----parent chimeras, the helper T cells were shown to affect TNP-Ficoll-responsive B cells in an H-2-unrestricted manner. The ability of T cells to mediate this IgG2a enhancement did not appear to be unique to any particular murine genetic background, because it was observed with T cells and nu/nu mice of C57BL/10, BALB/c, CBA/Ca, and B10.D2 strains. Priming of T cell donors with Ficoll or TNP-Ficoll did not increase the ability of splenic T cells, on a per cell basis, to enhance the IgG2a Ab response to TNP-Ficoll. The T cell population responsible for modulating the isotypic response was found to be sensitive to C-mediated cytotoxicity with both anti-Lyt-2 and anti-Lyt-1 hybridoma Ab. Although T cells from both the thymus and the spleen expressed enhancing activity, splenic T cells were more effective, on a per cell basis, than were thymocytes. The observations suggest that T cells that appear to enhance the switch to IgG2a in TNP-Ficoll-responsive B cells are not effectively primed by the antigen and interact with TNP-Ficoll-activated B cells through an H-2-unrestricted mechanism.
mesh_terms: D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology; D000954:Antigens, Surface / Q000235:genetics; D001402:B-Lymphocytes / Q000276:immunology*; D005362:Ficoll / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000276:immunology*; D006183:H-2 Antigens / Q000235:genetics; D007074:Immunoglobulin G / Q000096:biosynthesis* / Q000145:classification; D008211:Lymphocyte Cooperation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008819:Mice, Nude; D009578:Nitrobenzenes / Q000276:immunology*; D010641:Phenotype; D011134:Polysaccharides / Q000276:immunology*; D011828:Radiation Chimera; D013234:Stem Cells / Q000166:cytology / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000276:immunology*; D014301:Trinitrobenzenes / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000954:Antigens, Surface; D006183:H-2 Antigens; D007074:Immunoglobulin G; D009578:Nitrobenzenes; D011134:Polysaccharides; C020529:TNP-ficoll; D014301:Trinitrobenzenes; D005362:Ficoll