MCs incorporate donor DC-derived H2^b MHCII protein complexes. (A) SJL/J^B6 BM chimera were generated by BM transplantation from C57BL/6 donor mice (CD45.2⁺ H2^b MHCII) to SJL/J recipients (CD45.1⁺ H2^s MHCII). (B) CD45.2⁺ expression on skin DCs from SJL/J mice (n = 6) and SJL/J^B6 BM chimera 24 h after DNFB (n = 8) was assessed by flow cytometry. (C) CD45.1⁺ expression on skin MCs from SJL/J mice (n = 6) and SJL/J^B6 BM chimera 24 h after DNFB (n = 8). (D–F) Surface CD45.2 and intracellular H2^b MHCII expression by CD45.1⁺ recipient ear skin MCs (c-kit⁺FcεRI⁺) of SJL/J mice (D) and SJL/J^B6 BM chimera (E) 24 h after DNFB was measured by flow cytometry and quantified as box plot (F). ***, P < 0.001.