Similarly, the number
of BrdU+CD8β+ cells, BrdU+FoxP3+ cells, or total FoxP3+ cells in the portal area were counted. All counting was performed in a blinded fashion. The phenotypes of donor MHCII+ cluster-forming cells were analyzed, as reported previously,6 in fresh serial 2-μm cryosections of the parathymic LNs and graft liver. DCs in the liver nonparenchymal cells and hepatic lymph were defined as the MHCIIhighCD103high population, based on fluorescence-activated cell-sorting (FACS) data (Fig. 1A,D) and in accord with earlier studies.3, 12 Those DCs in the healthy MEK inhibitor rat liver could be subdivided into three phenotypically different groups: CD172a+CD11b+ DCs (∼44%); CD172a+CD11b− DCs (∼20%); and CD172a−CD11b+ DCs (∼28%) (Fig. 1A,B). Five days after sublethal irradiation, the total number of liver DCs decreased from ∼2.8 × 105 to ∼5.1 × 104 (Fig. 1C), and the percentages of the three subsets changed to ∼64%, ∼28%, and ∼5%, respectively (Fig. 1A,B). Notably, the CD172a−CD11b+ subset was radiosensitive and decreased dramatically after irradiation, but ∼25% of the other two subsets remained. MHCIIhighCD103high DCs in the Decitabine chemical structure hepatic lymph could also be subdivided into three phenotypically different groups: CD172a+CD11b+ (∼80%); CD172a+CD11b− (∼15%); and CD172a−CD11b+ DCs (∼3%) (Fig. 1D,E). Five days after
sublethal irradiation, the total number of lymph DCs decreased from ∼1.3 × 105 to ∼1.4 × 104 (Fig. 1F), and the percentages of the three subsets changed to ∼90%, ∼8%, and ∼1%, respectively
(Fig. 1D,E). Thus, among lymph DCs, the CD172a+CD11b+ subset was relatively radioresistant, with ∼13% remaining after irradiation, whereas the other two subsets were very radiosensitive and were almost abolished. As in our previous study,6 donor MHCII+ and donor MHCI+ cells readily migrated to the recipient’s secondary lymphoid organs (i.e., the spleen, skin LNs, this website and Peyer’s patches), and donor MHCII+ DCs formed clusters with recipient BrdU+ cells in the T-cell areas on days 1-3 after LT in the Irr(−) group (Supporting Fig. 1A,C). Because Peyer’s patches do not possess afferent lymphatics, DC entry should be through the blood, presumably through the high endothelial venules.6 FACS analysis of skin LNs (Fig. 2A) and Peyer’s patches (not shown) revealed that more than 90% of the migrated donor MHCIIhighCD103high DCs were CD172a+CD11b−. The exception was the parathymic LNs, in which both CD172a+CD11b− and CD172a+CD11b+ donor DCs were found (Fig. 2A); the CD172a+CD11b+ subset constituted ∼70% of all DCs. In the Irr(−) group, donor MHCII+ and MHCI+ cells appeared in the peritoneal cavity on days 1-3 after LT. There were comparable numbers of donor cells in the Irr(+) group (Fig. 3A).