title: Activation of B lymphocytes by monovalent anti-Lyb-2 antibodies.
abstract: Although activation of B lymphocytes by antigen or anti-Ig antibody has been shown to require cross-linking of surface Ig molecules, cross-linking is not necessary for B cell activation by anti-Lyb-2 monoclonal antibody (MAb). Monovalent Fab' fragments of anti-Lyb-2 MAb are as effective as the intact antibody in inducing blast cell transformation of small B cells and B cell proliferation in the apparent absence of T cells and adherent cells. In the presence of factors from T cells, B cells activated by Fab' fragments of anti-Lyb-2 MAb were induced to mature into Ig-secreting cells. Since monovalent Fab' fragments probably cannot induce receptor aggregation, it appears that receptor occupancy is sufficient to induce B cell activation with anti-Lyb-2 MAb.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000944:Antigens, Differentiation, B-Lymphocyte; D000950:Antigens, Ly / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D007140:Immunoglobulin Fab Fragments / Q000276:immunology*; D008213:Lymphocyte Activation; D046911:Macromolecular Substances; D051379:Mice; D008815:Mice, Inbred Strains; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000944:Antigens, Differentiation, B-Lymphocyte; D000950:Antigens, Ly; D000954:Antigens, Surface; D007140:Immunoglobulin Fab Fragments; D046911:Macromolecular Substances