TRANSFORMING GROWTH-FACTOR-BETA-1 MODULATES MURINE SPLEEN B-CELLS TO SECRETE ANTIGEN-SPECIFIC IGA ANTIBODY

It has been reported that transforming growth factor-beta 1 (TGF-beta 1) increases antigen (Ag)-nonspecific IgA secretion by LPS-stimulated sIgA(-) murine spleen B cells, and this effect is further augmented by costimulation with rIL-2. In contrast, IgM and IgG1 secretion are dow nregulated under the same conditions. The aim of this study was whethe r TGF-beta 1 could increase Ag-specific IgA synthesis by whole spleen cells. Mice were immunized with Ustilago maydis (UM) toxin and Ag-spec ific isotype antibody was measured by ELISA developed by us. TGF-beta 1 induced a 2-fold or greater increase in UM toxin-specific IgA secret ion by LPS-activated whole spleen cells from the immune mouse. Unexpec tedly, IgG1 production was also enhanced under the same conditions. In the case of immunization with BSA, TGF-beta 1 significantly increased BSA-specific IgA production, which was further augmented by IL-2. The se results from the present study indicate that TGF-beta 1 can induce spleen whole cells to secrete Ag-specific IgA production, raising the possibility that TGF-beta 1 may have important effects on the expressi on of Ag-specific IgA in vivo.