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 a nd 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 effec ts on CD25 expression, but significantly enhanced CD23 expression on t onsillar B cells. Interferon-gamma (IFN-gamma) exerted no inhibitory e ffect upon increases in CD25 or CD23 driven by CD40 ligation with sCD4 0L or anti-CD40 antibody. These data suggest that the induction of CD2 5 and CD23 genes by IL-4 is mediated. at least in part, by an IFN-gamm a-sensitive component, whereas gene activation driven via CD40 ligatio n involves signaling pathways which are not sensitive to IFN-gamma.