In vitro synthesis of IgE by human peripheral blood leucocytes. II modulation of IgE B cell activity by isotype-specific regulatory T cells.

IgE and IgG synthesis was demonstrated in cultures of isolated B cells from normal subjects, and those manifesting mild to severe atopy. Titration of autochthonous T cells into B cell cultures revealed both IgE isotype-specific T-help and T-suppression at low and high T:B ratios respectively. Increasing levels of help for IgG synthesis usually accompanied the stepwise addition of the same T cells to autochthonous or allogeneic B cells cultures. Experiments comparing the activity of putative IgE suppressor T cells in autochthonous versus allogeneic B cell cultures indicated that allogeneic interactions per se selectively inhibit IgE B cells. This finding seriously questions earlier conclusions of a causal relationship between suppressor cell deficiency and the expression of the allergic phenotype.