Interleukin-4-induced IgG subclass and IgE secretion by mononuclear cells from atopic donors.

To investigate the effect of interleukin-4 (IL-4) on the secretion of IgG subclasses and IgE in atopic individuals, peripheral blood mononuclear cells from 10 atopic and 10 normal donors were incubated with IL-4, and the production of IgE, IgG1, IgG2, IgG3, and IgG4 was determined after a 14-day culture period. Like normal peripheral blood mononuclear cells, atopic mononuclear cells were stimulated by IL-4 to secrete IgE and IgG4, but not the other IgG subclasses. This response was in the same quantitative ranges in both donor groups. Addition of interferon gamma to IL-4-containing cultures efficiently antagonized the IL-4-induced IgE and IgG4 secretion. These results do not support the hypothesis that an atopic condition is due to a discordant effect of IL-4 on IgE compared to IgG4 production or to an altered response to the potent antagonist interferon gamma.