[A method for the detection of suppressor lymphocytes and its clinical use]

Suppressor cells play a major role in immune regulation and supervision. Unspecific suppressor cells can be stimulated by Concanavalin A (ConA) in a concentration of 1-50 micrograms/ml. Absorbed pooled human AB serum is the optimal serum source. Monocytes are necessary to induce suppressor cells. Preincubation of lymphocytes abolishes the suppressor cell inducibility. Different ConA incubation periods show two suppressor peaks, the first on day 0-1, the second on day 4-6. It is concluded, therefore, that we deal with two populations of suppressor cells. The first of these seems to resemble the spontaneous in vivo suppressor level, needs not to be activated by ConA but is rapidly inactivated without permanent antigeneic stimulus. The second peak consists of suppressor cells which are activated by a ConA stimulation of at least 3-4 days. Another conclusion can be drawn from these data: The conventional control system for the ConA induction of suppressor cells is not the optimal one, because the spontaneous suppressor cells are not included within this system, although they perhaps give a better insight into the actual immune status.