SR/CR lymphocytes release effector molecules characteristic of necrosis. SR/CR mice were challenged with S180 cancer cells and the infiltrating leukocytes were analyzed for the expression of pfp, gzmA or gzmB. (A) SR/CR and WT mice were challenged with 10⁷ S180 cells. After 18 and 24 hours, the peritoneal cavities of the mice were washed with PBS and the cell pellets were removed. Cell-free supernatants were collected from WT and SR/CR (abbreviated SR) mice, and Western blots performed to determine if pfp, gzmA and gzmB were released during rupture of tumor cells. (B-D) SR/CR mice were challenged with 10⁶ S180 cells, and the mixed infiltrating leukocytes were washed from the peritoneal cavities of the mice after 45 min. The leukocytes were then cultured with S180 cells in vitro for 15 min at 39°C. Rosettes between leukocytes (arrows) and S180 cells (arrowheads) formed and were fixed with formalin. Slides were stained with antibodies against (B) pfp, (C) gzmA, or (D) gzmB, followed by a rhodamine-conjugated secondary antibody. Abbreviations: ph, phase contrast; rh, rhodamine. Figures shown here are representative of at least 5 separate experiments.