CD200hiITGA6hi cells localize to the hair follicle bulge and to the secondary germ.
(A) Gated population of CD200hiITGA6hi used for analysis in B, C, F, and G. (B and C) The majority of CD200+ cells were positive for the bulge markers KRT15 (B) and FST (C). (D–F) Ber-EP4 expression marked the secondary germ (D), and CD200 expression overlapped with Ber-Ep4 by double immunofluorescence (E) and flow cytometry (F). (E) Higher numbers of CD200+ cells were present in the upper (left) than in the lower (right) secondary hair germ. (G) As assessed by qPCR, sorted CD200hiITGA6hi cells were enriched in LGR5, a marker for activated bulge/secondary hair germ cells (n = 3). (H) Consistent with this enrichment, LGR5 expression was markedly reduced in bald scalp, whereas KRT15 was maintained, when tested by qPCR (n = 4). *P < 0.01. Scale bars: 100 μm. Numbers within dot plots indicate percent cells in the respective gate or quadrant.