Effect of acquired CCR7 on homing of NK cells to peripheral lymph nodes. (A) Xenogen IVIS Spectrum fluorescence image of XenoLight DiR-labeled NK cells that homed to peripheral lymph nodes 24 hours after intravenous administration. Individual lymph nodes resected from either the uninjected group or the group injected with XenoLight DiR-labeled CCR7⁻ or CCR7⁺ NK cells were placed in a 96-well plate; the columns of the plate represent right and left inguinal, axillary, and superficial cervical lymph nodes; and the rows represent individual animals. (B) Assessment of flux per region of interest drawn around each well that contained a single lymph node. Statistical analysis was performed with a nonparametric Wilcoxon test, and data are presented as median ± interquartile range (n = 30). The gray area depicts the range of flux because of autofluorescence.