The surrogate light chain in B-cell development

The proteins encoded by the V prB and λ s genes associate with each other to form a light (L) chain-like structure, the surrogate L chain. It can form Ig-like complexes with three partners - the classical heavy (H) chain, the D H J H C μ -protein, or the newly discovered p55 chain; these are expressed on the surface of pre-B cells at different stages of development. Here, Friz Melchers and colleagues review the structures of the V preB and λ s genes in mouse and their relatives in humans, describe their pattern of expression, and speculate on their possible evolution and functions.