title: In vitro immune response of human peripheral lymphocytes. V. PHA- and protein A-induced human B colony formation and analysis of the subpopulations of B cells.
abstract: Human B colony formation was observed with PHA or protein A as a mitogen. Preculture of B cells with mitogens in the presence of irradiated T cells for 3 days was a prerequisite for the induction of B cell colonies. About 300 to 700 colonies per 10(6) seeded cells were detected and a linear relationship between the number of cells seeded and the number of colonies developed was observed. Cells in PHA-induced colonies had surface IgM and/or IgD but no cytoplasmic Ig, whereas cells recovered from protein A-induced colonies had cytoplasmic Igs that were not only IgM but IgG and IgA. In each of the protein A-induced colonies, a sequential appearance of IgM-, IgG-, and IgA-producing cells was observed from day 3 to day 5, showing that IgM-, IgG-, and IgA-producing cells were derived from a single precursor cell. PHA and protein A had an additive effect on the number of colonies induced. About 50% of colonies induced in the presence of both PHA and protein A had Ig-producing cells. These results suggest that PHA and protein A may stimulate distinct subsets of B cells into colony formation.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000145:classification; D002478:Cells, Cultured; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D007111:Immunity, Cellular; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008214:Lymphocytes / Q000276:immunology*; D010835:Phytohemagglutinins / Q000494:pharmacology*; D011817:Rabbits; D013205:Staphylococcal Protein A / Q000494:pharmacology*
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D010835:Phytohemagglutinins; D013205:Staphylococcal Protein A