Behavior of Human Foreskin Keratinocytes Expressing a Hair Follicle Stem Cell Marker CD200  Atsushi Terunuma, Justin W. Cross, Michelle Dyke, Veena Kapoor, William G. Telford, Jonathan C. Vogel  Journal of Investigative Dermatology  Volume 128, Issue 5, Pages 1332-1334 (May 2008) DOI: 10.1038/sj.jid.5701154 Copyright © 2008 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 1 CD200(+) keratinocytes in human neonatal foreskin epidermis. (a and b) Foreskin epidermis contains CD200(+) cells that are distinct from c-kit(+) melanocytes and CD45(+) cells. (c) CD200(+) CD45(−) c-kit(−) cells (gray tinted area) are positive for keratin 5 and negative for keratin 10. Dotted line: isotype control; thick line: total population of CD45(−) c-kit(−) cells. (d and e) CD200(+) keratinocytes are medium in size, and enriched for α6 integrin-bright/CD71-dim cells. Journal of Investigative Dermatology 2008 128, 1332-1334DOI: (10.1038/sj.jid.5701154) Copyright © 2008 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 2 In vitro colony formation assay and in vivo competitive repopulation assay. (a and b) CD200(+) keratinocytes exhibit low colony-forming efficiency, whereas α6 integrin-bright/CD71-dim keratinocytes show higher colony-forming efficiency than total epidermal keratinocyte control. One set of experiments consisted of six replicates of flasks for each population of cells; only one flask of each population is shown in (a). Four independent sets of experiments were carried out as shown in (b). (c and d) α6 integrin-bright/CD71-dim keratinocytes, but not CD200(+) keratinocytes, expand to increase the population sizes in skin grafts on the backs of nude mice during 4–5 months of chase period. Total, α6-bright CD71-dim and CD200(+) keratinocytes were purified from a single pool of HLA-A2(+) primary epidermal cells, and mixed with HLA-A2(−) cultured keratinocytes to prepare human skin equivalents, in which 0.5% of epidermal cells were HLA-A2(+). Human skin equivalents were grafted on the backs of nude mice, and stably maintained for 4–5 months. Grafts were harvested and the percentages of HLA-A2(+) human keratinocytes (indicated by gates in c) were measured. Representative flow cytometry data of human skin grafts are shown in (c). Results of two independent sets of experiments are shown in (d). Journal of Investigative Dermatology 2008 128, 1332-1334DOI: (10.1038/sj.jid.5701154) Copyright © 2008 The Society for Investigative Dermatology, Inc Terms and Conditions