The molecules controlling B lymphocytes.

The need to activate B lymphocytes on antigen challenge is tempered by the requirement that the response is terminated when the challenge has been negotiated. Regulation is probably mediated via the interaction of soluble factors with surface receptors. Here, John Gordon and Graeme Guy review recent work that has focused on the actions of the soluble regulatory mediators and on the surface molecules they may interact with - emphasizing the growing importance of the CD23 antigen.