title: B-1 B cell development in the fetus and adult.
abstract: Models of hematopoiesis often depict lymphocyte production as a uniform process in which a homogenous population of hematopoietic stem cells (HSCs) generates progenitors from which all types of lymphocytes are derived. However, it is increasingly evident that these schemes are too simplistic and that the lymphoid potential of HSCs and precursors arising in the embryo, fetus, neonate, and adult is remarkably distinct. We review recent findings regarding the development of B lymphocytes, and the B-1 B cell lineage in particular, as a case in point. These studies show that B-1 and B-2 B cells involved in innate and adaptive immune responses, respectively, arise in staggered waves of development from distinct progenitors. We discuss the implications of this layered model of B cell development for understanding normal and dysregulated B lymphopoiesis.
authors.affiliation: Department of Pathology and Laboratory Medicine, The David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
authors.forename: Encarnacion
authors.initials: E
authors.lastname: Montecino-Rodriguez
authors.forename: Kenneth
authors.initials: K
authors.lastname: Dorshkind
mesh_terms: D056704:Adaptive Immunity; D001402:B-Lymphocytes / Q000145:classification / Q000166:cytology / Q000276:immunology; D019070:Cell Lineage; D005333:Fetus / Q000166:cytology* / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate