Enhancement of heterotransplanted human tumor graft survival in nude mice treated with antilymphocyte serum and in congenitally athymic-asplenic (Lasat) mice.

The latency period, success rate, and minimal cell inoculum size required for transplantation of continuously passaged human tumor lines into congenitally athymic (nude) mice, antilymphocyte serum (ALS)-treated congenitally athymic (nude) mice, and congenitally athymic-asplenic (lasat) mice were compared. The 11 tumor lines studied included examples of breast adenocarcinoma, transitional cell carcinoma, osteosarcoma, fibrosarcoma, Hodgkin's disease, malignant melanoma, and rhabdomyosarcoma. Of these 11 tumor lines, 3 were successfully transplanted into nude mice, compared to 5 of 10 tumor lines in ALS-treated nude mice and 9 of 11 lines in lasat mice. Moreover, the latency period was shorter and the minimal cell inoculum size was lower for lasat mice than for either nude or ALS-treated nude mice. Despite this enhancement of heterotransplantation into lasat mice and despite the growth of large local masses, no evidence of distant metastases was found.