title: Inhibition of T cell activation in vivo with mixtures of monoclonal antibodies specific for I-A and I-A/E molecules.
abstract: (CBA x B6)F1 (Iak x Iab) T cells were activated to sheep erythrocytes in irradiated F1 mice in the presence of various monoclonal anti-Ia reagents and then tested for their capacity to collaborate with B cells from B10.BR (I-Ak, I-Ek) (kk), B10.A(4R) (kb), and B10 (bb) mice. Anti-I-Ak antibodies blocked the generation of help for B10.A(4R) B cells, but not B10.BR or B10 B cells. An anti-I-Ab antibody blocked help for B10 B cells, but not for B10.BR or B10.A(4R) B cells. An antibody (Y-17) specific for I-Ak/Ek and I-Ab/Ek molecules, but not for I-Ak or I-Ab molecules, failed to impair the generation of help for B10.BR, B10.A (4R), or B10 B cells. In marked contrast to injecting each antibody separately, a mixture of anti-I-Ak and anti-I-Ak,b/Ek (Y-17) antibodies virtually abolished the generation of help for B10.BR B cells. A mixture of anti-I-Ak and anti-I-Ab antibodies effectively blocked help for (4R x B10)F1 B cells, i.e., cells expressing hybrid I-A molecules. These two antibodies only marginally impaired help for (CBA x B6)F1 B cells. To block help for (CBA x B6)F1 B cells required selection in the presence of a cocktail of anti-I-Ak, anti-I-Ab, and anti-I-Ak,b/Ek antibodies. The implications of these findings are discussed.
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D001667:Binding, Competitive; D000939:Epitopes; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008808:Mice, Inbred CBA; D012756:Sheep; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000906:Antibodies; D000911:Antibodies, Monoclonal; D000939:Epitopes; D000949:Histocompatibility Antigens Class II