Recent studies have provided considerable insight into the mechanism of BCR-mediated B-cell activation, but the inhibitory signals transferred by Fc gamma Rs leading to down-regulation of BCR-activated B lymphocytes are not clarified yet. In the present paper the authors give an overview on new findings regarding BCR structure and signal transduction mechanisms induced by the B-cell antigen receptor complex and outline, partly based on their own observations, the possible mechanisms resulting in Fc gamma R-mediated inhibition of B cells.