Anti-tumour immunity by normal allogeneic blood transfusion in rat

Growth of transplantable KMT-17 tumour in syngeneic WKA/MK rats was inhibited by i.v. preimmunization with whole blood from normal rats of allogeneic strains. The inhibitory effect was also observed in rats immunized with allogeneic white blood cells alone. The strength of the inhibitory effect mainly depended on the the strain of donor rat used; blood from Donryu and Kyoto strain rats produced the strongest inhibition, blood from Tokyo and Fischer strain rats produced moderate inhibition to the syngeneic tumour growth. Blood from ACI/N strain rats did not produce the inhibition. The mechanism of blood transfusion in inhibiting tumour growth is not yet clear. However, it seems that GVH reaction does not play an important role in the mechanism of the inhibition effect, because the effect was obtained by immunization with mitomycin C-treated allogeneic white blood cells and also by the immunization effect may be due to nonspecific active immunization. Significance of blood transfusion with special reference to clinical immunogtherapy of cancer is discussed.