Enhancement of specific immunoglobulin production in SCID-hu-PBL mice after in vitro priming of human B cells with superantigen.
Priming of human mature B cells in vitro with staphylococcal enterotoxin A (SEA) prior to transplantation of the B cells into severe combined immunodeficiency (SCID) mice, together with human T-helper cells, resulted in higher and more uniform concentrations of serum IgG in the mice. This indicated that a large number of B cells had become activated, which was supported by the finding that SEA priming resulted in production of immunoglobulin displaying a more normal kappa/lambda ratio than was obtained in the absence of SEA priming. However, IgM concentrations were not affected by SEA priming. Immunization of mice, transplanted with SEA-primed B cells, with both primary and secondary antigens resulted in a high specific IgG response to both types of antigen. The elevated levels of specific antibodies were not merely the consequence of an unspecific stimulation of B cells caused by SEA, as the ratio of specific antibody to total IgG was much higher in animals receiving SEA-primed B cells. Thus, a co-operative effect on immunoglobulin production of stimulating B cells via surface immunoglobulin and help delivered by SEA-activated T-helper cells was indicated. A specific antigen-dependent IgM response to a secondary antigen was observed as well, but was, in contrast to the IgG response, not influenced by SEA priming of B cells. No IgM antibodies with reactivities to the primary antigens were detected in the SCID sera at any time-point after immunization. The results thus indicate that SEA might replace T-cell epitopes in antigens and efficiently recruit an abundance of T-cell help to B cells, resulting in enhanced production of specific IgG antibodies.
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D004768:Enterotoxins / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007075:Immunoglobulin M / Q000096:biosynthesis; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D016513:Mice, SCID; D013047:Specific Pathogen-Free Organisms; D013211:Staphylococcus aureus / Q000276:immunology*; D018089:Superantigens / Q000276:immunology*
D004768:Enterotoxins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D018089:Superantigens; C026066:enterotoxin A, Staphylococcal