B-cell antigen receptor competence regulates B-lymphocyte selection and survival

Experimental evidence contradicts the simplistic view that during developme nt all B cells expressing non-autoreactive antigen receptors on the cell su rface are selected into the mature B-cell pool. While allelic exclusion, cl onal selection and affinity maturation continue to define the mainstream no tions of B-cell development and selection, new evidence is redefining our u nderstanding of these processes. Receptor editing replaces functional B-cel l receptors by secondary immunoglobulin gene rearrangements, a process that can play roles in both immune tolerance and immune response. In addition, editing can rescue cells that would otherwise fail positive selection. We f ocus here on our studies indicating that the functional competence of the B -cell antigen receptor complex plays a central role in the fate of developi ng B cells and their antigen receptor genes.