FIG. 1.
Cell line differences in tumorigenicity in adult nu/nu rats and susceptibility of NK cells. (A) Four-week-old female nu/nu rats were subcutaneously inoculated with 107 F344-S1 (●) or TARS-1 (■), W7TM-1(▴), TART1(▵), and MT-2(□) cells. The tumor size was measured once every week and expressed in cubic millimeters by the formula described in Materials and Methods. Results are indicated as means ± standard deviations in each group of two or three rats. Similar results were obtained in two independent experiments. (B) F344-S1(●), TARS-1(■), W7TM-1(▴), TART1(▵), MT-2(□), P815(○), and YAC1 (⧫) cells were labeled with 51Cr for 1 h and used as target cells. Nylon wool-passed splenocytes from nu/nu rats were used as effectors at various E/T ratios, as indicated. Results are indicated as mean percent lysis ± standard deviation.