Effect of cytokines on spontaneous and allergen-induced CD23 expression, sCD23 release and Ig(E,G) synthesis from peripheral blood lymphocytes.

We studied the expression of the CD23 antigen as well as the release of soluble CD23 from peripheral blood lymphocytes (PBL) of atopic donors. PBL were stimulated with allergen (Dermatophagoides pteronyssinus; Der.p.), cytokines (interleukin-4, interferon-gamma; IL-4, IFN-gamma) or combinations of stimuli. CD23 levels were enhanced after the addition of allergen or IL-4 (10 U/ml) up to 10-fold compared to spontaneous expression. Soluble CD23 (sCD23) release was enhanced in a dose-dependent manner by allergen or IL-4. The combined addition of IL-4 and allergen resulted in an expression of CD23 as well as sCD23 release from PBL that was higher compared to the effects obtained with a single component. The production of Ig(E,G) increased in the presence of IL-4 (10 U/ml). This effect was enhanced after the addition of allergen. In contrast, the addition of allergen alone did not modulate IgE synthesis but revealed an enhanced IgG synthesis. Spontaneous as well as allergen- or IL-4-induced CD23 expression was significantly reduced in the presence of IFN-gamma, whereas the concomitant sCD23 release was enhanced in a dose-dependent fashion. IgE synthesis (spontaneous, IL-4 induced) was suppressed in the presence of IFN-gamma. IFN-gamma also reduced the IL-4-enhanced IgG secretion, whereas the spontaneous IgG production was not affected.