[Cellular kinetics of the primary immune response after application of phytohemagglutinin]

The Jerne technique, a proved method for detecting the number of plaque-forming cells (PFC) in spleen, shows an immunosuppressive effect of phytohemagglutine (PHA) on primary immune response. Kinetic studies are done on 300 NMRI mice, considering the number of PFC/10-8 spleen cells. Significant suppressions of the primary immune response are found if PHA is applied either one day before or together with antigen provided that studies are done 3, 4 or 5 days after immunization with sheep red blood cells (SRBC). The role of activated T-lymphocytes concerning the diminution of immune response is discussed.