Chemotherapy and immunotherapy of three human lymphomas serially transplantable in the neonatal Syrian hamster

Three lymphomas, serially transplantable in Syrian hamster neonates, have been derived by intraperitoneal implantation of lymphoblasts from the peripheral blood of two pediatric patients with lymphosarcoma that had undergone progression to acute lymphoblastic leukemia. Two of the neoplasms are serially transplantable in normal, untreated Syrian hamster neonates. The third is transplantable only in neonatal hamsters treated with rabbit antiserum to hamster thymus cells, antilymphocyte serum, (ALS). None is transplantable in adult hamsters. These experimental tumors in the hamster neonate have been examined for their responses to chemotherapy, immunotherapy, or both. Agents were administered in a single dose intraperitoneally, 7 days after implantation. Methotrexate more effectively controlled tumor growth than did 6-MP, prednisone, Cytoxan, vincristine, actinomycin D, or D54 · naponate (listed roughly in decreasing order of effectiveness). An antiserum made in rabbits against the human tumor cells was ineffective when administered at 7 days, but highly inhibitory in the first 1–3 days. Immunization of the mother with tumor cells at 23–75 days before littering prevented tumor growth in neonatally challenged offspring. Treatment of the neonate with spleen cells derived from adult normal or specifically sensitized hamster donors was also effective in inhibiting tumor growth. The data suggest that human lymphoma serially transplantable in the newborn hamster may constitute a system practical for the study of potentially useful chemotherapeutic or immunotherapeutic agents. Such a system might be especially applicable in the study of chemical agents which are active against human cells in vitro but inactive in standard mouse tumor assays in vivo.