Effects of interleukin-4(B cell stimulatory factor-1) on B cell growth and differentiation = Interleukin-4(B cell stimulatory factor-1)의 B임파구 성장 및 분화에 대한 작용

Abstract

Interleukin-4(IL-4), a 20,000 dalton glycoprotein produced by activated T-cells, has been re-port-ed to have pleiotropic effects on immune and hematopoietic systems. We studied various biologi-cal effects of IL-4 on the growth of B-cells and T-cells as well as on the B-cell differentiation and maturation. Using [3H] thymidine incorporation as an index for B-cell proliferation, we performed IL-4 bioassay employing anti-IgM costimulation method. Human recombinant IL？4 induced active proliferation of purified tonsillar B cells in the presence of insolubilized anti-IgM antibody at the optimal concentration of 5신g/ml. The soluble anti-IgM was ineffective. By examining the ability of T cell culture supernatant to induce B-cell proliferation, the optimal culture condition of T-cells for the effective IL-4 production was found to be the combined treatment with PHA lO/eg/ml and PMA 20ng/ml. IL-4 increased the expression of membrane FceR H (low affinity receptor for IgE： CD23) and soluble FceR n in a dose-dependent manner indicating that IL-4 could be involved in IgE production and immediate type hypersensitivity. In contrast to the reported effects of IL-4 on the immunoglobulin production and IgGi isotype switch in the murine system, we did not observe such effects with the human system, which may require more sensitive assay methods. IL-4 also induced proliferation of activated tonsillar T-cells but did not have any effects on resting T-cells. Detailed elucidation of mechanisms underlying these various biological activities of IL-4 would require the characterization, purification and molecular cloning of IL-4 receptor.