Figure 7.

NK cells and IFN-γ are necessary for innate editing of a regressor tumor and M1 macrophage accumulation. Regressor cell line 2 was transplanted into RAG2^−/− mice treated with anti-NK1.1, IFN-γ–blocking antibody, or control antibody, after which tumor growth was measured and passaged cell lines were generated. (A and B) The passaged cell lines were then transplanted into syngeneic WT hosts (number of cell lines and mice are indicated) and tumor-free survival was measured. Tumor-free mice were defined to have a nonenlarging mass <9 mm in average diameter by day 40. Tumor sections from RAG2^−/− hosts were stained for MHC class II (C) and quantitated (D). *, P < 0.05. Error bars are represented by ± SEM. Results were reproduced at least once.