B16F10 cells associated with leukocytes in lungs. B16F10 cells labeled with CFSE were injected into mouse tail veins. (A) After 48 hours, lungs were digested and analyzed for presence of CFSE-B16F10 as in Figure 2D (left panels). In addition, CFSE⁺ cells (gated as in left panels) were stained with CD45-allophycocyanin (anti-CD45 monoclonal antibody conjugated with allophycocyanin; right panels). Note that CFSE⁺ cells were essentially absent in the sample from a control mouse with no B16F10 injection (bottom panels). (B) CFSE⁺ cells from digested lung cell preparations were analyzed to determine the percentage of CD45-associated cells (as in panel A). Error bars indicate means ± SEM. WT indicates wild-type; KO, knockout.