Donor T cells induce variable turnover of Langerhans cells. Ears from transplanted mice were analyzed for LC turnover by the LC-migration assay (A-B) and by immunofluorescence (C). To identify LCs (A), we gated on ethidium monoazide-negative cells (left panel) that were Langerin⁺MHCII⁺ (second panel) Note that nearly all MHCII⁺ cells express Langerin. We gated on MHCII⁺Langerin⁺ cells and determined the fractions that were host- or donor-derived based on expression of CD45.1 or CD45.2 (right panels). (B) Scatter plot of data analyzed as per panel A; each symbol represents data from an individual mouse. P < .03 comparing T-cell recipients to their respective BM-alone controls (data combined from 2 independent experiments with similar results). (C) Immunofluorescence staining. Epidermal preps were costained for expression of CD45.2 (red), MHCII (green), and Langerin (gray). Langerhans cells are present in recipients of BM only, but they are host-derived (CD45.2⁻; top row). With donor CD8 cells, donor CD45.2⁺ LCs engraft (second row), but engraftment is focal. Shown is an area of donor LCs abutting residual host LCs (see overlay of CD45.2 and MHCII staining in the third panel). The bottom 2 rows are staining of samples from CD45.1 and CD45.2 control mice. Images were originally captured with 200× magnification.