Macrophage transmission of suppressor signal for suppression of delayed hypersensitivity and humoral response in JEV-infected mice.

Japanese encephalitis virus (JEV) infection induces suppressor T-cells (Ts1) which suppress both the humoral (Ts-PFC) and cell mediated (Ts-DTH) immune response by producing soluble suppressor factors. This study shows that in the JEV model, both TS-PFC and Ts-DTH mediate suppression by recruiting a second subpopulation of suppressor T-cells, the Ts2-PFC and Ts2-DTH. The signal between Ts1 and Ts2 is transmitted by macrophages (M phi). The suppressor factors are adsorbed by peritoneal or splenic M phi. Both heat-killed and live M phi are capable of adsorbing suppressor factors but only live M phi are capable of presenting the signal to T-cells. Thus these are at least two generations of suppressor T-cells in the JEV-specific suppressor pathway and the presence of M phi is obligatory for transmission of the signal.