title: Activation and proliferation signals in mouse B cells. V.A. comparison of the effects of intact (IgG) and F (ab')2 anti-mu or anti-delta antibodies.
abstract: This study compares the effects of soluble intact (IgG) and F(ab')2 rabbit anti-mu and anti-delta antibodies on mouse B cells. The results show that while the F(ab')2 antibodies to both isotypes induce polyclonal B cell proliferation, the IgG antibodies are not mitogenic, but rather inhibit DNA synthesis induced by the homologous F(ab')2 fragments. Furthermore, intact anti-mu antibodies inhibit mitogenesis induced by F(ab')2 anti-delta, and vice versa. However, the intact antibodies to both isotypes promote early changes characteristic of B-cell activation, namely, increased Ia antigen expression, and priming for a facilitated proliferative response to F(ab')2 anti-Ig. In addition, F(ab')2 anti-mu and anti-delta both induce the breakdown of phosphatidylinositol phospholipids in B cells, an early consequence of Ig receptor cross-linking which may be involved in the induction of cell growth. These results therefore indicate that stimulating mature B cells via IgM or IgD receptors produces indistinguishable early effects, and that cross-linking Fc and surface Ig receptors by intact anti-Ig generates a dominant inhibitory signal, regardless of which isotype is involved.
authors.forename: G G
authors.initials: GG
authors.lastname: Klaus
authors.forename: M K
authors.initials: MK
authors.lastname: Bijsterbosch
authors.forename: R M
authors.initials: RM
authors.lastname: Parkhouse
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D007072:Immunoglobulin D / Q000276:immunology; D007140:Immunoglobulin Fab Fragments / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology; D007138:Immunoglobulin delta-Chains / Q000276:immunology; D007148:Immunoglobulin mu-Chains / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D010716:Phosphatidylinositols / Q000378:metabolism; D011817:Rabbits
chemical_list: D000949:Histocompatibility Antigens Class II; D007072:Immunoglobulin D; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007138:Immunoglobulin delta-Chains; D007148:Immunoglobulin mu-Chains; D010716:Phosphatidylinositols