ANTIGEN-DEPENDENT REGULATION OF IGE ANTIBODY-PRODUCTION BY HUMAN ANTIGEN-SPECIFIC B-CELLS

As-specific B cells from the peripheral blood of immunized donors were separated following rosette formation with tetanus toxin (TT)-coupled immunobeads to study the regulation of T cell-dependent Ab production , Surface IgM(+) (slgM(+)) B cells rosetting with TT-coated beads prod uced anti-Ht IgM, Igc, and IgE Abs in cultures stimulated with EBV or anti-CD40 Ab in the presence of IL-4; this was associated with increas ed numbers of B cells positive for slgC and slgE. TT-binding slgM(+) B cells also produced significant amounts of anti-TT IgM, Igc, and IgE Abs when they were cultured with autologous T cells in the presence of IL-4, Addition of TT to the IL-4-stimulated, T cell-dependent culture s resulted in higher levels of TT-specific IgM and IgG Abs than observ ed with T cells alone, but the inclusion of TT with T cells suppressed anti-TT IgE production, Addition of TT Ag to cultures with allogeneic T cells failed to enhance IgM and Ige responses, and the inhibition o f IgE production was reduced compared with cultures containing autolog ous T cells in the presence of Ag. These results demonstrate thai the presence of Ap contributes to the regulation of Ab production, resulti ng in enhanced IgM and Ige responses, but down-regulation of IgE Ab pr oduction.