In vivo and in vitro Activity of Tolerant Anti-leukæmia Serum

Abstract

IN previous work we have shown that after the induction of artificial immunological tolerance in the rabbit to normal mouse tissues, subsequent immunization with tumour produces tolerant anti-tumour sera. These show low murine toxicity and significantly greater toxicity for the tumour than do non-tolerant anti-tumour sera or anti-sera against normal tissues—tolerant or non-tolerant. So far we have prepared such tolerant specific antisera against the transplantable Ehrlich ascites tumour^1,2 and the spontaneous AKR lymphatic leukæmia^3,4. The assays of these anti-sera have been done in vivo. Other workers have also reported tolerant specific anti-tumour sera using both homologous^5–8 and isologous^9,10 tumours.