FIG. 4. Tumor-infiltrating A-NK cells depend on IL-2 for survival.
GFP+ and GFP+,IL-2+ A-NK cells were produced by stable transduction of Mau-1 cells (a long-term A-NK-cell line (C57BL/6) developed in our lab) with adeno-associated virus containing the gene for GFP or the genes for both GFP and IL-2. (A) DIC picture of a B16 lung tumor from an animal injected i.v. with 5 million IL-2- and GFP-producing Mau-1 cells 72 h earlier. (B) Fluorescence picture of the tumor shown in (A) showing numerous GFP+ cells infiltrating the tumor. (C) DIC picture of a B16 lung tumor from an animal injected i.v. with 5 million GFP-producing Mau-1 cells 72 h earlier. (D) Fluorescence picture of the tumor shown in (A) showing very few GFP+ cells infiltrating the tumor. No exogenous IL-2 was given to support the injected Mau-1 A-NK cells. Bars = 100 μm.