Macrophage migration from the peritoneum to the lymph nodes. A mixture of PKH67-labeled WT and PKH26-labeled Mac-1^-/- macrophages (i) or PKH67-labeled WT and PKH26-labeled WT macrophages (ii) were separately injected intraperitoneally into the WT mice, followed by intraperitoneal injections of PBS or LPS. Four hours later, the number of the adoptively transferred WT and Mac-1^-/- macrophages within the peritoneum was analyzed by dual-color FACS analysis (A), and their migration into the lymph nodes was visualized by fluorescence microscopy of the corresponding frozen sections (B). The data shown are representative of 2 independent experiments.