Figure 3.

Growth of reconstituted and unreconstituted RAD-gR.28 cells in wild-type and immunodeficient mice. (A) Rejection of reconstituted RAD-gR.28.mgR in 129/Sv/Ev mice. IFN-γ-insensitive RAD-gR.neo (▴) or RAD-gR.mgRΔIC (•) tumor cells and IFN-γ-sensitive RAD-gR.28.mgR (▪) cells were injected subcutaneously at a dose of 10⁶ cells per animal into 129/Sv/Ev mice. RAD-gR.28.mgR cells were also injected subcutaneously into 129/Sv/Ev mice that had been pretreated on days −1, +2, and +5 with i.p. injections of 250 μg of a neutralizing mAb to murine IFN-γ (⧫) or saline (data not shown). (B) RAD-gR.28.mgR is resistant to the antiproliferative actions of IFN-γ. Triplicate cultures of RAD-gR.28.neo and RAD-gR.28.mgR cells were incubated for 24 hr with different combinations of IFN-γ (5,000 units/ml), IFN-α (1,000 units/ml), TNFα (10 ng/ml), IL-1 (10 ng/ml), and IL-12 (50 units/ml), and proliferation was assessed by monitoring ³H-labeled thymidine incorporation. Values are expressed as the percentage of incorporation compared with untreated cells. (C) RAG1^−/− mice cannot reject reconstituted, IFN-γ-sensitive RAD-gR.28.mgR cells. RAD-gR.28.mgR cells were injected subcutaneously at a dose of 10⁶ cells per mouse into either 129/Sv/Ev (▴) or RAG1^−/− (▪) mice. Values represent the average ± SE tumor diameter of four to five mice per group.