title: Functional maturation of B cells in vitro.
abstract: Maturation of B-cell function was studied in a two-stage tissue culture system. In the first stage, cells were cultured in the absence of antigen and then transferred to microcultures where the frequency of hapten-specific plaque-forming cell (PFC) precursors was determined; Bone-marrow cells and spleen cells from 6--8-day-old mice mice were shown to act as sources of B-cell neogenesis in vitro. Both populations had very low initial frequencies of hapten-specific PFC precursors, but this increased ten- to seventeen-fold during a period of 72 h in the preliminary cultures. This increase could not be accounted for by selective cell death, nor by decay of a suppressor cell subpopulation nor by proliferation of pre-existing Fc-receptor-bearing B cells. The mechanism for the increase in frequency of functional B cells in cultures of bone marrow and neonatal spleen was thus the result of maturation of B-cell precursors to a state of immune competence during the culture interval.
mesh_terms: D000367:Age Factors; D000818:Animals; D000917:Antibody Formation; D000921:Antibody-Producing Cells; D001402:B-Lymphocytes / Q000254:growth & development / Q000276:immunology*; D001854:Bone Marrow Cells; D002478:Cells, Cultured; D000939:Epitopes; D006462:Hemolytic Plaque Technique; D007158:Immunologic Techniques; D051379:Mice; D008807:Mice, Inbred BALB C; D013154:Spleen / Q000166:cytology
chemical_list: D000939:Epitopes