FIG. 7.

Regression of the growth of FPM1-V1AX cells induced by FPM1-immunized T cells. (A) T cells were isolated from nu/+ rats that had been inoculated with FPM1 or age-matched naive nu/+ rats. Four-week-old nu/nu rats were subcutaneously inoculated with 2 × 10⁷ FPM1-V1AX cells alone (■) or simultaneously with intraperitoneal inoculation of 10⁷ of the immunized (●) or naive (○) T 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 three independent experiments. (B) FPM1-V1AX (circles) or FPM-SV (squares) cells were labeled with ⁵¹Cr for 1 h and used as target cells. Nylon wool-passed splenocytes from FPM1-immunized nu/+ rats (open symbols) or naive nu/+ rats (closed symbols) were used as effectors at various E/T ratios, as indicated. Results are indicated as mean percent lysis ± standard deviation.