Stimulation of human blood lymphocyte by different polyclonal B cell activators of bacterial and plant origin: production of IgM, IgG and IgA estimated by the ELISA method.

Lymphocytes isolated from peripheral blood of healthy donors were stimulatedin vitro with pokeweed mitogen, concanavalin A, flagellin,Nocardia delipidated cell mitogen (NDCM) and heat-killed bacteriaEscherichia coli andActinomyces viscosus. A simple and sensitive technique, enzyme-linked immunosorbent assay (ELISA) was used for the detection of nanogram levels of IgM, IgA and IgC in media from lymphocyte cultures after polyclonal stimulation, Pokeweed mitogen, NDCM andE. coli were shown to stimulate a high production of IgM; after stimulation withA. viscosus a higher production of IgA was detected. No immunoglobulin production was observed after stimulation with polymerized flagellin.