Fidelity and infidelity in commitment to B-lymphocyte lineage development

Abstract

During B-lymphocyte development in mouse fetal liver and bone marrow, a pre-B I cell stage is reached in which the cells express B-lineage- specific genes, such as CD19, Igα and Igβ, and V(preB) and λ5, which encode the surrogate light (SL) chain. In these pre-B I cells both alleles of the immunoglobulin heavy (IgH) chain locus are D(H)J(H) rearranged. Transplantation of pre-B I cells from wild-type (e.g. C57Bl/6) mice in histocompatible RAG-deficient hosts leads to long-term reconstitution of some of the mature B-cell compartments and to the establishment of normal IgM levels, a third of the normal serum IgA levels, and IgG levels below the detection limit. Neither T-lineage nor myeloid cel..