title: Human B lymphocyte subsets. I. IgG-bearing B cell response to pokeweed mitogen.
abstract: The subset of B lymphocytes having IgG on their surfaces was purified from human spleen and blood using a fluorescence-activated cell sorter (FACS). This subset constituted about 15% of B lymphocytes. The remaining non-IgG-bearing B cells were also obtained for study. These two populations were examined for (a) their expression of other surface immunoglobulin isotypes, (b) their ability to give rise to IgG- and IgM-secreting (plaque-forming) cells in a pokeweed mitogen (PWM)-driven culture system, and (c) their ability to proliferate in response to PWM stimulation. The results of these studies indicate that most IgG-bearing B cells also express surface IgM and IgD. Less than 15% had only IgG. The IgG-positive cell gave rise to both IgG and IgM plaque-forming cells when driven by PWM, and in fact were responsible for most of the total plaque response in both the IgG and IgM classes. The non-IgG-bearing B cells were depleted of both IgG and IgM responsiveness. The failure of the non-IgG-bearing B cells to give a strong response to PWM did not appear to be due to either depletion of accessory cells or to any suppressive influence. Finally, proliferation studies indicated that both the IgG-bearing and the non-IgG-bearing cells proliferated in the presence of PWM with a somewhat stronger proliferative response in the IgG-bearing cells. These results demonstrate that the IgG-bearing cell is not irreversibly committed to IgG production but can also give rise to IgM-secreting cells, and that human PWM-driven immunoglobulin secretory responses are predominantly due to a numerically small subset of B cells.
mesh_terms: D001402:B-Lymphocytes / Q000145:classification* / Q000166:cytology / Q000276:immunology; D002450:Cell Communication; D002455:Cell Division; D006462:Hemolytic Plaque Technique; D006801:Humans; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011043:Pokeweed Mitogens / Q000494:pharmacology*; D011947:Receptors, Antigen, B-Cell; D013154:Spleen / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011043:Pokeweed Mitogens; D011947:Receptors, Antigen, B-Cell