[Activation by injectable gamma globulins of the suppressive functions of the humoral response tested in vitro].
In subjects with normal immune system injectable gammaglobulins produce unexpected effects: B cells become unable to mature into plasmocytes in vitro when cultured in the presence of pokeweed mitogen. This inhibitory effect seems to be associated with binding of the denatured gammaglobulins to B cell membrane receptors for the IgG Fc fragment (Fc gamma). In addition, injectable gammaglobulins activate a radiosensitive suppressor T cell population without Fc receptors for IgG. Activation of the suppressive function inhibiting of B cells into plasmocytes results from excessive secretion of prostaglandin E2 (PGE 2) by monocytes. We have previously demonstrated that PGE 2 in excess activates certain suppressor T cells. The secretion of PGE 2 by monocytes is thought to be associated with the binding of denatured IgG's to membrane receptors for the corresponding Fc. Activation of suppressor T cells was reproduced in vitro by incubating total T cells or T cells without Fc gamma receptors in the presence of either complete gammaglobulins or of the aggregates they contain. In contrast, preparations deprived of aggregates and F (ab)'2 fragments isolated from gammaglobulins do not produce any detectable activation of suppressor T cells. The results obtained in vitro may not necessarily correspond to the effects of injectable gammaglobulins on humoral response in vivo. We should point out, however, that a fall in plasma IgE levels may be observed in some subjects and that in exceptional cases of IgG and IgA hypergammaglobulinaemia a fall in IgG and IgA has been recorded after gammaglobulin injections.
D000917:Antibody Formation / Q000187:drug effects*; D001402:B-Lymphocytes / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D066298:In Vitro Techniques; D007273:Injections, Intramuscular; D008213:Lymphocyte Activation; D009000:Monocytes / Q000378:metabolism; D011043:Pokeweed Mitogens; D011458:Prostaglandins E / Q000378:metabolism; D011947:Receptors, Antigen, B-Cell / Q000276:immunology; D011961:Receptors, Fc / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D005719:gamma-Globulins / Q000008:administration & dosage*
D011043:Pokeweed Mitogens; D011458:Prostaglandins E; D011947:Receptors, Antigen, B-Cell; D011961:Receptors, Fc; D005719:gamma-Globulins
Activation par les gammaglobulines injectables des fonctions suppréssives de la réponse humorale testée in vitro.