Production and secretion of immunoglobulins by in vitro-activated human B lymphocytes

Activation induced by pokeweed mitogen in cultures of mononuclear cells from human blood was followed sequentially by simultaneous quantitation of live cells, thymidine incorporation, cells displaying cytoplasmic, IgM, IgG, IgA or IgD, cells secreting IgM, IgG or IgA and cumulated IgM secretion. Maximal cellular activity was found after 7 days of cultures, with means of 16000 IgM-, 20700 IgG- and 9900 IgA-secreting cells per 10(6) originally cultured cells. The cumulated IgM secretion after 21 days of culture averaged 10400 ng per 10(6) originally cultured cells. A close correlation was found between the number of IgM-secreting cells and the cumulated IgM secretion.