Figure 2.

Impaired acute in vivo rejection of tumor cells due to selective reduction of peripheral NK1.1⁺ CD3⁻ cells. (A) Selective reduction of peripheral NK1.1⁺ CD3⁻ cells in Tg mice. Cells prepared from indicated tissues were stained with anti-NK1.1 and anti-CD3. The numbers represent the percentage of cells within the quadrant among all viable cells. (B) Mice were inoculated i.v. with ¹²⁵I-Udr-labeled 3 × 10⁵ YAC-1 tumor cells. After 4 hr, the residual lung radioactivity was measured. Results are expressed as the mean % residual radioactivity ± SD from three to five mice per group. (C) Reconstituted tumor clearance by scid splenocytes. Scid mice that were pretreated with anti-NK1.1 or untreated were injected i.p. with poly-I:C on day −1. Two hours after i.v. infusion of PBS or 8 × 10⁶ splenocytes isolated from anti-NK1.1-treated or untreated scid mice, the recipient mice were inoculated i.v. with ¹²⁵I-Udr-labeled 3 × 10⁴ RMA-S tumor cells. After 6 hr, the residual lung radioactivity was measured. Results are expressed as the mean percentage residual radioactivity ± SD from three mice per group. Where indicated for B and C, anti-NK1.1-treated mice received an i.p. injection of 200 μg of anti-NK1.1 mAb 2 days before tumor inoculation.