Cell and cell-free transplantation experiments with a mouse reticulum cell sarcoma

Quantitative cellular assays of the transplantability of 19 spontaneous reticulum cell sarcomas (RCS) of the BC3F1 mouse were carried out by injecting serial dilutions of monodispersed cells into syngeneic hosts through the intravenous, intracranial and subcutaneous routes. A clear relationship was found between the size of the inoculum and the incidence of tumour takes by all routes, but even for inocula of 5 million cells only 13 tumors grew in one or more of the transplanted recipients. The intravenous route of injection was found to be the most effective, both in terms of the absolute number of tumor takes and the number of cells necessary to produce a given level of takes. The survival of the animals injected intravenously was related to the number of cells received in that earlier deaths occurred with the most concentrated cell suspensions. Attempts to transmit the tumor by cell-free extracts injected into newborn or 1-month-old syngeneic hosts failed to substantiate the possible presence of a specific leukemogenic agent.