Blood Supply--Susceptible Formation of Melanin Pigment in Hair Bulb Melanocytes of Mice

www.PRSGlobalOpen.com 1 Skin grafts from syngeneic strains of mice onto C57BL/6 mice (ie, isografts) are tolerated, whereas those from allogeneic (eg, BALB/c) strains of mice (ie, allografts) are rejected.1 The alloreactive immune response is predominantly di-rected at the major histocompatibility complex (H-2 in mice) class I molecules,2–11 and the rejected skin is replaced by surrounding skin with black hair.5,12 Un-expectedly, however, mostly gray-colored hair grows on the syngeneic skin grafts to cover the original size of the grafts.12 Mature melanocytes are melanin-synthesizing dendritic cells located within the basal layer of the epidermis, hair bulb, and outer root sheath of hair follicles.13 Hair melanin is formed by melanocytes situated in the hair bulb epithelium around the Disclosure: The authors have no financial in-terest to declare in relation to the content of this article. This study was supported, in part, by the program Grants-in-aid for Young Scientists (B) (grant no. 22791740 and 22791741) from th