IMPROVED ENGRAFTMENT OF HUMAN TUMORS IN SCID MICE PRETREATED WITH RADIATION AND ANTI-ASIALO GM1

The effects of sublethal radiation (3 Gy) and anti-asialo GM1 (anti-AS GM1) on engraftment of human tumour cell lines and fresh tumour were e valuated in the severe combined immunodeficient (SCID) mouse. Four tum our cell lines (colonic adenocarcinoma LS174T, malignant melanoma MEWO , lung adenocarcinoma H125, chronic myelogenous leukemia K562) and a f resh colon cancer metastasis were injected subcutaneously, intraperito neally or intravenously into SCID mice. Tumour volume and metastatic s pread of implanted tumours were evaluated 3-8 weeks following inoculat ion. Pretreatment with radiation and anti-ASGM1 resulted in more rapid and extensive uptake of subcutaneous and intraperitoneal tumours. Tai l vein injection into pretreated animals also resulted in a greater nu mber of lung metastases of H125, MEWO and K562 cell lines. This study demonstrates that sublethal radiation and the elimination of murine NK cell activity with anti-ASGM1 improves tumour take rates. These findi ngs should prove useful for investigations of human cancer immunothera py using SCID mice engrafted with human lymphocytes and human tumours.