The action of tuftsin on the reaction of macrophage-suppressor formation in vitro and in vivo

A cell suspension consisting of nonadhering and adhering spleen cells in the ratio 30:1 was incubated in a 10(-4) M tuftsin's solution during 15-30 min. The addition of 10(7) cells incubated in tuftsin syngeneic recipients resulted in the suppression of the immune response of the latter to sheep red blood cells. It was noted that this effect may be induced by using adhering cells only of intact donors and only when incubated together with nonadhering cells. The addition of tuftsin one hour after transplantation of the nonadhering spleen cells resulted in the suppression of the immune response. It was proposed, that suppression effect released through generation of the macrophage-suppressors.