NATURAL KILLER CELL-ACTIVITY IN RETICULUM-CELL SARCOMAS (RCS) OF SJL-J MICE

Two transplantable reticulum cell sarcomas (RCS) of SJL mice expressed marked levels of natural killer (NK) activity when tested against susceptible 51Cr-labeled tumor targets. In contrast, normal SJL lymph node and spleen cells demonstrated low levels of NK activity. Neither depletion of macrophages nor pretreatment with anti-Thy-1.2 sera and complement reduced the capacity of RCS cells to express NK activity. Systemic injection of irradiated RCS cells into SJL mice induced a transient increase in NK activity at 3 and 7 days after injection. However, the NK activity observed in recipients of irradiated RCS cells never reached levels comparable to those of control mice injected with viable tumor cells. These data suggest that the transplantable reticulum cell sarcomas of SJL mice may represent a tumor of natural killer cells and thus provide an enriched source of these effectors that may be useful for further characterization of natural cytotoxicity. © 1979.