Receptor editing in positive and negative selection of B lymphopoiesis.

In B lymphopoiesis, Ag receptor expression and signaling are critical to determine developmental progression, survival, and activation. Several positive and negative selection checkpoints to test this receptor have been described in B lymphopoiesis, aiming to ensure the generation of functionally competent, nonautoimmune repertoire. Secondary Ag receptor gene recombination allows B lymphocytes to replace an inappropriate receptor with a new receptor, a mechanism called receptor editing. This salvage mechanism uncouples the Ag receptor fate from that of the cell itself, suggesting that B cell repertoire is regulated by a process of receptor selection. Secondary rearrangements are stimulated in different stages of B cell development, where editing of the receptor is necessary to fulfill stage-specific requirements. In this study, we discuss the contribution of receptor editing in B lymphopoiesis and its regulation by positive and negative selection signals.