Lymphocyte activation. VI. A re-evaluation of factors affecting the selectivity of polyclonal mitogens for mouse T and B cells.

In the culture and assay systems described here the majority of mouse spleen cells stimulated by soluble concanavalin A and phytohaemagglutinin have been shown to be T cells, whereas bacterial endotoxin (LPS) stimulates B cells almost exclusively. These observations appear to be independent of the tissue source, the length of the culture period, and the presence of supernatants from other cultured T cells. Pokeweed mitogen (PWM) is capable of stimulating both T and B cells, the relative numbers of each probably being affected by the length of the culture period and variability between different PWM samples. Preliminary evidence is presented for mature LPS-responsive cells being able to persist for long periods in the mouse peripheral lymphoid system. The importance of using culture conditions that allow selective stimulation of T and B cells is discussed, especially in relation to their accurate quantitation.