Suppression by IL-2 of IgE production by B cells stimulated by IL-4.

IgE production was obtained from B cells of BALB/c or nude mice when these cells were cultured with IL-4 plus LPS. IL-2 added to these cultures at the start (day 0), 1 or 2 days later completely suppressed the production of IgE. The production of IgG1 was also inhibited, but only if IL-2 was added on day 0. The production of other isotypes (IgM, IgG2a, IgG2b) was only slightly decreased by addition of IL-2. No suppression of IgE or IgG1 production was observed if monoclonal anti-IL-2 was added, whereas anti-IFN-gamma had no effect on the suppression of the production of these isotypes. The expression of CD23 on the third day of culture on B cells stimulated with LPS and IL-4 was markedly decreased when IL-2 was added to the cultures on day 0. Addition of monoclonal anti-IL-2 suppressed all effects produced by IL-2, whereas addition of anti-IFN-gamma had no effect. These results show that the suppression by IL-2, at least for the first signaling processes, are different from the suppression produced by IFN-gamma.