Surrogate light chains (λ5 and
VpreB)
-Expressed transiently :
production of λ5 mRNA
stops as soon as pre-B cell receptor formed
-pre-B receptor signaling via
accessory chains
stops heavy chain rearrangement
-Induces proliferation
-
-Large pre-B cells divide several
times (expand
30X to 60X)
-Resting small pre-B cells
-RAG re-expressed for L chain rearrangement
-
-Single pre-B cell can generate
different antigen
specificities (B cell diversity)