Regulation of antibody response by an IgG-anti-Ig autoantibody occurring during alloimmunization. I. A few IgG molecules inactivate one B cell.
We have shown previously that alloimmunized rats develop a broadly reactive IgG-antiimmunoglobulin autoantibody in addition to antidonor antibodies. The findings presented herein demonstrate that this "physiological" antibody suppresses antigen receptor-induced IgM production of B cells derived from rats of the same strain. When affinity-purified IgG-anti-Ig was added to cell cultures, the antibody production of B cells was maximally inhibited at the minute concentration of 0.9 pg/10(6) cells. Higher or lower IgG-anti-Ig concentrations resulted in weaker suppression. The same result was obtained when spleen lymphocytes were used instead of purified B cells. Based on the molecular weight of IgG and Avogadro's number, our results indicate that a few molecules of IgG-anti-Ig are sufficient to inhibit the antibody production of a single B cell. Activity at this minuscule concentration demonstrates that IgG-anti-Ig antibodies are exquisitely active immunoregulatory molecules. In addition to the stimulatory effect of IgM-anti-Ig rheumatoid factors reported by others, our findings define the second component of an immunoregulatory mechanism: suppression of the B cell response by an IgG-anti-Ig autoantibody produced during alloimmunization.
Terness
P
P
Department of Transplantation Immunology, University of Heidelberg, Germany.
Opelz
G
G
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000096:biosynthesis*; D000917:Antibody Formation; D001323:Autoantibodies / Q000096:biosynthesis*; D001402:B-Lymphocytes / Q000276:immunology*; D007114:Immunization; D007074:Immunoglobulin G / Q000276:immunology*; D008297:Male; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew
D000888:Antibodies, Anti-Idiotypic; D001323:Autoantibodies; D007074:Immunoglobulin G