Fig. 2.
Formation of leukocyte rosettes during the killing of cancer cells in SR/CR mice. SR/CR mice were challenged i.p. with 107 S180 cells, and infiltrating peritoneal leukocytes were harvested after 24 h and analyzed to determine which leukocyte subsets were present in rosettes. (A) Composition of leukocyte subsets in the rosettes. Cytopreps were prepared and stained with cell-specific markers for each leukocyte subset. The percentage of each subset was quantified by direct counting. (B) Contact site morphology of rosettes. The contact sites between cancer cells (T) and PMN (arrowhead) and MΦ (arrow) were viewed by transmission electron microscopy. (C) Immunofluorescence microscopy of rosettes. SR/CR mice were injected i.p. with GFP-transfected S180 cells, and responding leukocytes were removed and analyzed by light microscopy. (a) Phase-contrast view of a rosette. (b) DAPI staining showing nuclear morphology. (c) GFP fluorescence of S180. (d) Rhodamine-conjugated anti-NK1.1 labeling of leukocytes in the rosette (arrows). (e) Composite picture of S180 and anti-NK1.1 staining in a rosette.