Growth of human tumors in lethally irradiated mice reconstituted with syngeneic fetal liver cells.

Transplantation into lethally irradiated mice of hematopoietic and lymphoid cells from immature donors which hypothetically will not mount a cell mediated attack against simultaneously inoculated human tumor cells has resulted in tumor engraftment and growth in long-term surviving radiation chimeras. Twenty-four hours after lethal irradiation, A or CBA mice were given iv injections of 2 X 10(7) fetal liver cells from syngeneic donors of 14, 16, or 18 days of embryonation and sc injections of 1, 3, or 6 X 10(6) human choriocarcinoma (C-1, C-2, and C-3) cells or human breast carcinoma (B-1) cells that had been maintained in culture. Palpable tumors greater than or equal to 5 mm were noted in 18/22 mice injected with C-1, 9/16 with C-2, 10/10 with C-3, and 18/30 with B-1. Tumors of 17 (31%) of mice remained palpable until death of the animal or until termination of the experiment 100 days post inoculation. Histologic study of autopsy specimens revealed malignant tumors with occasional pulmonary metastases. Human chorionic gonadotropin was found in the serum of mice that received choriocarcinoma cells.