Soluble CD40 ligand induces expression of CD25 and CD23 in resting human tonsillar B lymphocytes

In this report, we describe the dose‐dependent increase in both CD25 and CD23 levels on resting human B cells in response to CD40 ligation, as mediated by soluble CD40 ligand (sCD40L) or anti‐CD40 antibody. In combination with interleukin (IL)‐4, sCD40L had limited additive effects on CD25 expression, but significantly enhanced CD23 expression on tonsillar B cells. Interferon‐γ (IFN‐γ) exerted no inhibitory effect upon increases in CD25 or CD23 driven by CD40 ligation with sCD40L or anti‐CD40 antibody. These data suggest that the induction of CD25 and CD23 genes by IL‐4 is mediated, at least in part, by an IFN‐γ‐sensitive component, whereas gene activation driven via CD40 ligation involves signaling pathways which are not sensitive to IFN‐γ.