CX3CR1⁺ LPCs, but not CD103⁺ DCs, display long-term persistence in small bowel transplants. (A) CD45.2⁺ intestinal fragments were grafted into CD45.1⁺ recipients and analyzed by fluorescence microscopy. 6 d after transplantation, the majority of CD11c⁺MHCII⁺ (arrows) cells in the grafted tissue did not express CD45.2, i.e., had been replaced by host cells. In contrast, CD11c⁺ cells with low MHCII signal (arrowheads) were mostly CD45.2⁺, which is indicative of donor origin and long-term persistence in the grafted tissue. Bars, 50 µm. Six mice were analyzed in six experiments. (B) Intestinal fragments were grafted from CX3CR1^+/GFP donors into WT recipients. 9 d after transplantation, the number of CX3CR1/GFP⁺ cells in the grafted tissue was enumerated by epifluorescence microscopy and compared with unmanipulated CX3CR1^+/GFP mice (control). Error bars represent SD. Bars, 20 µm. Two mice were analyzed in two experiments. (C) CX3CR1^+/GFP mice were injected i.p. with 2 mg BrdU and, 9 h later, the percentage of BrdU-positive CD103⁺ DC and CX3CR1⁺ LPC was determined by flow cytometry. Six mice were analyzed in three independent experiments. Error bars represent SEM. Results were obtained with a Wilcoxon signed rank test. *, P < 0.05.