In vivo activity of syngeneic CD8⁺ NKT cells after injection into tumor-bearing hosts.

Bcl1 tumor cells (H-2^d; 10³) were injected intraperitoneally into syngeneic Balb/c recipient animals. After 7 days, animals were lethally irradiated (400 cGy ×2) and some animals were rescued with 10⁶ syngeneic (H-2^d) BM with or without syngeneic ex vivo–expanded CD8⁺ NKT cells (H-2^d). Length of animal survival was assessed. All animals that died after day 20 had clear evidence of Bcl1 tumor growth assessed by massive splenomegaly. ▵ indicates XRT (n = 5); ○, BM (n = 5); and ■, NK − T + BM cells (n = 15).