Immunoglobulins (Ig) production by peripheral blood mononuclear cells (PBMC) from 27 healthy subjects at the 6th and 12th day of in vitro stimulation by pokeweed mitogen (PWM) or bacterial lipo-polysaccharide (LPS) was investigated. Total IgG, IgA, IgM in the culture supernatants were measured by an enzyme linked immunosorbent assay (ELISA). The average values of Ig production (in ng per ml of culture supernatants) under PWM and LPS stimulation after 12 days of culture are respectively: 3397 and 2557 for IgG, 512 and 374 for IgA, 3172 and 1439 for IgM. The use of PWM and LPS mitogens for stimulating Ig secreting cells may provide insights into the nature of the interacting cells on immune responses and into the pathogenesis of different diseases.