GVT activity is preserved in the absence of donor-derived IL-15. (A) Lethally irradiated wt B6D2F1 mice received 2000 log-phase P815 cells, 5 × 106 wt B6 splenic T cells, and 1 × 107 TCD BM cells from either wt B6 (wt allo, ▪, n = 12) or IL-15–/– B6 (IL-15–/– allo, □, n = 12) mice. As controls, identical mice received 5 × 106 wt B6D2F1 (syngeneic) T cells and 1 × 107 wt B6D2F1 TCD BM cells plus (syn (+), •, n = 5) or minus (syn (-), ○, n = 5) 2000 P815 cells. Animals were monitored daily after transplantation and survival times were compared using the logrank test. Results are combined from 3 similar experiments. (B) Livers were harvested from representative moribund recipients. Paraffin sections were stained with toluidine blue. Slides were reviewed by a board-certified veterinary pathologist in a blinded fashion. Tumor rests are indicated by the white vertical arrows. Magnification = ×40.
