A natural IgM antibody does inhibit polyclonal and antigen-specific IgM but not IgG B-cell responses.
Since a B-cell growth-inhibitory natural IgM antibody was identified in the culture supernatants of LPS-stimulated murine splenic B lymphocytes [11], attempts have been made to define other possible functional role(s) of this antibody. Here we show that this regulatory IgM is able to inhibit not only the proliferation of splenic B cells, but also their IgM secretion during LPS-induced polyclonal, as well as antigen (FITC-KLH)-specific antibody responses. In contrast, IgG1 production of hapten (FITC)-specific B cells neither during restimulation with LPS nor in the presence of carrier-specific T lymphocytes in vitro was affected by regulatory IgM. Therefore, whereas newly emerging naive B cells are highly susceptible, IgG-secreting B cells appear to be completely resistant to inactivation by the regulatory IgM autoantibody.
Kiss
K
K
Department of Immunology, Loránd Eötvös University, Göd, Hungary.
Uher
F
F
Gergely
J
J
D000818:Animals; D000918:Antibody Specificity / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000378:metabolism; D006241:Haptens / Q000276:immunology; D006433:Hemocyanins / Q000031:analogs & derivatives / Q000378:metabolism; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000502:physiology*; D008070:Lipopolysaccharides / Q000276:immunology; D051379:Mice; D008811:Mice, Inbred DBA; D017634:Self Tolerance; D012710:Serum Albumin, Bovine; D013154:Spleen / Q000166:cytology
D000939:Epitopes; D006241:Haptens; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008070:Lipopolysaccharides; C039217:fluorescein isothiocyanate bovine serum albumin; C088472:fluorescein isothiocyanate-keyhole limpet hemocyanin; D012710:Serum Albumin, Bovine; D006433:Hemocyanins; D016650:Fluorescein-5-isothiocyanate