Figure 3.

Mechanisms of negative selection during B-cell development. There are three described mechanisms whereby developing B cells can escape an autoreactive fate; all of these are mediated by signals transduced through the B-cell receptor (BCR) in response to BCR ligation and are indicated by red arrows. Which outcome results is largely a function of BCR signalling intensity, developmental stage and environmental milieu. Receptor editing is postulated to be a result either of retarded progression from the pre-B to immature B-cell stage, or of back-differentiation from the immature to pre-B-cell stage. Anergy is induced in immature bone marrow B cells as a response to receptor ligation, whereas deletion is induced in transitional B cells in response to the same stimulus.