title: A novel anti-Ia monoclonal antibody which specifically enhances the corresponding T cell alloreactivity.
abstract: An anti-I-Ab monoclonal antibody, designated K14.83-11, was produced in a fusion between SP 2/0 Ag-14 myeloma cells and spleen cells from a B10.D2/n mouse primed in vivo against C57BL/10. Unlike other anti-I-Ab monoclonal antibodies thus far described, K14.83-11 was found to have a combination of features involving specificity, isotype, and function, unique among existing anti-I-A reagents. K14.83-11 exhibited a strong binding to the I-Ab gene product, with only slight cross-reactivity to the I-Ap/q family of allelic products and no reactivity towards I-Ak,d. When analyzed for isotype, K14.83-11 was found to be of a rare IgG3 isotype. With respect to biologic activity, K14.83-11 not only failed to produce the expected inhibition of specific anti-I-Ab T cell reactivity in vitro, but instead produced a striking enhancement of T cell responses against the I-Ab gene product. The possible relationship of IgG isotype and function was suggested when the immunoenhancing effect of K14.83-11 on reactive T lymphocytes was reversed to that of suppression with highly purified F(ab)2 fragments obtained by pepsin digestion.
mesh_terms: D000276:Adjuvants, Immunologic / Q000502:physiology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000502:physiology*; D000918:Antibody Specificity; D001666:Binding Sites, Antibody; D002460:Cell Line; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007074:Immunoglobulin G / Q000502:physiology; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D007074:Immunoglobulin G