title: B-Lymphopoiesis in Fetal Liver, Guided by Chemokines.
abstract: Early in embryonic development of mice, from day 12.5 after conception, myeloid-lymphoid bipotent progenitors, expressing receptors both for IL7 and CSF-1, migrate from embryonic blood into developing fetal liver. These progenitors also express multiple chemokine receptors, i.e., CCR7, CXCR3, CXCR4, and CXCR5, all on one cell. Their migration through LYVE-1+ vascular endothelium is guided by CCR7, recognizing the chemokine CCL19, and by CXCR3, recognizing CXCL10/11, chemokines which are both produced by the endothelium. Once inside fetal liver, the progenitors are attracted by the chemokine CXCL12 to ALCAM+ liver mesenchyme, which produces not only this chemokine, but also the myeloid differentiation-inducing cytokine CSF-1 and the lymphoid differentiation-inducing cytokine IL7. In this mesenchymal environment B-lymphocyte lineage progenitors are then induced by IL7 to enter differentiation and Ig gene rearrangements. Within 3-4 days surface IgM+ immature B-cells develop, which are destined to enter the B1-cell compartments in the peripheral lymphoid organs.
authors: Research Group on "Lymphocyte Development," Max Planck Institute for Infection Biology, Berlin, Germany.
authors: K
authors: K
authors: Kajikhina
authors: Research Group on "Lymphocyte Development," Max Planck Institute for Infection Biology, Berlin, Germany; Reproductive Centre, Mio Fertility Clinic, Yonago, Japan.
authors: M
authors: M
authors: Tsuneto
authors: Research Group on "Lymphocyte Development," Max Planck Institute for Infection Biology, Berlin, Germany. Electronic address: fritz.melchers@unibas.ch.
authors: F
authors: F
authors: Melchers
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D018925:Chemokines / Q000378:metabolism*; D047109:Fetal Development; D005333:Fetus; D006801:Humans; D008099:Liver / Q000502:physiology*; D038041:Lymphopoiesis; D008648:Mesoderm / Q000502:physiology*; D051379:Mice; D054448:Precursor Cells, B-Lymphoid / Q000502:physiology*; D054400:Receptors, CCR7 / Q000378:metabolism
chemical_list: C515370:CCR7 protein, human; D018925:Chemokines; D054400:Receptors, CCR7
keywords: B-cell development; Chemokines; Fetal liver; Liver mesenchyme; Transendothelial migration