Characterization of B-cell populations bearing Fc epsilon receptor II.

We have characterized the B-cell population that expresses low affinity Fc receptors for IgE (Fc epsilon RII). Fc epsilon RII+ B cells from normal adult BALB/c mice expressed high levels of surface IgD and low/medium levels of surface IgM and constituted the majority of mature splenic B cells. Fc epsilon RII+ splenic B cells expressed high levels of class II MHC antigens and medium to high levels of B220, and consisted of approximately equal numbers of J11dhigh and J11dlow cells. CD5+ B cells did not appear to be Fc epsilon RII+, and interleukin 4 did not induce Fc epsilon RII expression on CD5+ B cells. Fc epsilon RII was not expressed by B cells that had differentiated to secrete immunoglobulin but was expressed on activated B cells. These data suggest that Fc epsilon RII is a differentiation marker expressed on mature and activated B lymphocytes in the major B-cell lineage.