title: Putative B lymphocyte lineage precursor cells in early murine embryos.
abstract: The emergence of putative B lymphocyte lineage cells in embryonic and neonatal tissues of mice was studied using monoclonal antibodies which recognize virtually all B cells, pre-B cells and an additional population of lymphoid cells. An extensive survey of extraembryonic and intraembryonic hemopoietic tissues indicated that cells displaying this marker first appear within liver of 45-50 somite stage embryos. Prior to this developmental stage, none were found in yolk sac or peripheral blood. Although some 14.8 antigen bearing cells were found in suspensions of ectoplacenta, these were small surface IgM+ lymphocytes which were presumably of maternal origin. Culture of embryonic liver fragments which initially contained small numbers of antigen positive cells resulted in their expansion. However, this did not occur when very early liver rudiments containing virtually no lymphoid cells were cultured. These findings document the earliest appearance of cells during ontogeny which may be committed to differentiate into functional B lymphocytes.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation; D004622:Embryo, Mammalian / Q000166:cytology / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D008099:Liver / Q000166:cytology / Q000276:immunology; D051379:Mice; D008808:Mice, Inbred CBA; D009924:Organ Culture Techniques
chemical_list: D000911:Antibodies, Monoclonal