Interleukin 4 and interferons alpha and gamma regulate Fc epsilon R2/CD23 mRNA expression on normal human B cells

Human interleukin 4 (IL-4) upregulates Fc epsilon R2/CD23 expression on the surface of B lymphocytes. Here it is shown that IL-4 induces expression of CD23 mRNA in normal human B lymphocytes whereas recombinant IL-1, IL-2, IL-5, IFN gamma, IFN alpha 2b and semi-purified low molecular weight B cell growth factor were unable to do so. CD23 mRNA expression could be observed in B cells after 6 hr incubation with IL-4 and was maximal for 24-72 hr. Costimulation of the B cells with anti-IgM antibody enhanced the IL-4 induced CD23 mRNA expression. In contrast, IFN gamma and IFN alpha 2b inhibited IL-4 induced CD23 mRNA expression in normal B lymphocytes. Thus the regulatory effects of IL-4 and interferons on the CD23 membrane expression are linked to an increase and a decrease of CD23 transcripts respectively.