Inhibition of pokeweed mitogen-induced immunoglobulin production in humans by gold compounds.

The effect of gold compounds on an in vitro model of antibody production was investigated. Peripheral blood mononuclear cells from healthy adult individuals were stimulated with pokeweed mitogen (PWM) and generation of immunoglobulin secreting cells (ISC) was assayed. Addition of gold sodium thiomalate 10 microgram/ml markedly inhibited mitogen-induced ISC production. The suppression of Ig production could not be explained by nonspecific lymphocyte toxicity or interference with the assay system. Inhibition of PWM responsiveness was mediated directly by the gold moiety and was not a function of the thiomalate. Furthermore, it was shown that maximum suppression of ISC generation occurred only when gold was added to cultures within the first 24 hours of incubation. This suggested that gold compounds inhibit an early step in B cell activation and differentiation rather than merely blocking Ig secretion by mature plasma cells.