Studies on human peripheral blood lymphocytes in vitro. II. Morphological and biochemical studies on the transformation of lymphocytes by pokeweed mitogen.

A study of the kinetics of RNA and DNA synthesis in PWM-stimulated lymphocytes revealed that RNA synthesis preceded the onset of DNA synthesis by approximately 24 hr and that DNA synthesis and transformation was maximal between 66 to 78 hr. Histochemical and radioautographic studies on PWM stimulated cultures indicated that at 72 hr 50 to 60% of the cell population had been transformed by PWM, and that a distinct cell type bearing cytologic resemblance to the early plasma cell had emerged. The RNA sedimentation profile for newly synthesized RNA in PWM-stimulated cells showed that a large peak of 45 to 50 S material was formed after 24 and 40 hr. PWM thus produces a distinctive transformation of human peripheral blood lymphocytes.