title: In vitro differentiation of B lymphocytes from pre-B cells.
abstract: Adult bone marrow contains both B lymphocytes and their immediate precursors, pre-B cells. These two cells differ in size and can be separated by velocity sedimentation; B cells are enriched in the subpopulation of cells sedimenting at between 2.0 and 3.5 mm/hr and pre-B cells in the subpopulation between 5.0 and 7.0 mm/hr. Incubation of pre-B cells in vitro for 4 or 5 days leads to their differentiation into functional B lymphocytes. The transition form pre-B to B appears to occur in two steps. The first step gives mitogen responsive B cells with an intermediate sedimentation velocity and the second step produces typical small, slowly sedimenting B cells. Pre-B cells can be quantified by using a limiting dilution assay and occur at a frequency of 1/60 in the subpopulation of rapidly sedimenting bone marrow cells.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology*; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002469:Cell Separation; D002478:Cells, Cultured; D005260:Female; D007075:Immunoglobulin M / Q000096:biosynthesis; D008198:Lymph Nodes / Q000166:cytology; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008934:Mitogens / Q000494:pharmacology; D013997:Time Factors
chemical_list: D007075:Immunoglobulin M; D008934:Mitogens