B cell differentiation and interleukin 2 (IL 2): corticosteroids interact with monocytes to enhance the effect of IL 2

摘要

AbstractUponin vitroactivation byStaphylococcus aureusCowan I strain (SAC) human peripheral blood B cells produce only marginal amounts of Ig when cultured in the presence of interleukin 2 (IL2; 10 U/ml). This response is only moderately increased by the addition of monocytes or of IL1. In the presence of dexamethasone (DM; 10−7−10−8M) microgram amounts of both IgM and IgG are produced in co‐cultures of B cells and monocytes. This response is not modified by inhibitors of cyclooxygenase and is specifically inhibited by a monoclonal antibody interfering with the binding of IL2 to its receptor. This enhancing effect of DM is not observed in the absence of monocytes even if IL 1 is added to the cultures. Moreover, monocytes pretreated with DM stimulate the response of B cells cultures in the absence of DM. Enhancement of Ig production by DM and monocytes could be demonstrated with B cells obtained from a patient suffering from a hyperlymphocytic form of B cell type chronic lymphocytic leukemia, and in this case only IgM was produced. Importantly, DM fully inhibited the IL2‐dependent proliferation of these monoclonal B cells. Thus, physiological concentrations of DM can modulate monocytic function to enhance the differentiative effe