ABERRANT B-CELL DEVELOPMENT AND IMMUNE-RESPONSE IN MICE WITH A COMPROMISED BCR COMPLEX

The immunoglobulin alpha (Ig-alpha)-Ig-beta heterodimer is the signali ng component of the antigen receptor complex on B cells (BCR) and B ce ll progenitors (pre-BCR). A mouse mutant that lacks most of the Ig-alp ha cytoplasmic tail exhibits only a small impairment in early B cell d evelopment but a severe block in the generation of the peripheral B ce ll pool, revealing a checkpoint in B cell maturation that ensures the expression of a functional BCR on mature B cells. B cells that do deve lop demonstrate a differential dependence on Ig-alpha signaling in ant ibody responses such that a signaling-competent Ig-alpha appears to be critical for the response to T-independent, but not T-dependent, anti gens.