Leukemia: serial transplantation of human leukemic lymphoblasts in the newborn Syrian hamster.

Human leukemia cells are being regularly grown intraperitoneally in the intact newborn Syrian hamster as 3 serially transplantable sublines of lymphosarcoma. These sublines, established from suspension cultures of human leukemic lymphoblasts (CCRF-CEM cells) by the implantation of large numbers of cells, exhibit similar transplantation and growth characteristics, and are presently in their llth, 8th, and 6th serial passages, respec tively. The intraabdominal lymphosarcomas frequently metastasize to the central nervous system, and in some instances progress to leukemia—a striking recapitulation of the human disease from which the CCRF-CEM cells were originally isolated. Immunofluorescence evidence clearly indicates the presence of human species-specific antigens in the cells of the serially trans planted lymphosarcomas. The morphology of these cells, as determined by electron micrography, does not differ significantly from that of the CCRF-CEM cells in suspension culture. There is as yet no morphologic evidence for the presence of virus asso ciated with growth of these cells, either in suspension cultures or