Evidence for clustering of H-2K, H-2D, and the Fc receptor on the membranes of B cells.

Alloantisera to H-2K, H-2D, and Ia antigens markedly inhibited the binding of EA but not FITC-IgG by the B cell Fc receptor. EA rosette formation approached normal levels when masked H-2 but not Ia specificities were allowed to cap on the membranes of B cells. beta2-mu coated SRBC were bound by the Fc receptor, and high concentrations of soluble beta2-mu were found to moderately inhibit EA rosette formation while lower concentrations enhanced binding. The data support the concept of Fc/Ia identity, and they suggest that H-2K, H-2D, and the Fc receptor may be closely grouped on the membranes of B cells. Further, these observations suggest that the beta2-microglobulin associated with H-2 could serve to link T cells with the Fc receptor of B cells during the inductive phase of antibody synthesis.