A subpopulation of human basal keratinocytes has a low/negative MHC class I expression.
By means of flow cytometry, we demonstrate that a subpopulation of cells in the basal layer of the human epidermis has undetectable levels of major histocompatibility complex (MHC) class I molecule. The percentage of MHC class I-negative cells in the basal layer ranged 0.5%-2%. MHC class I-negative cells were characterized by small size (low forward scatter) and low granularity (low side scatter). Upon culturing of MHC class I-negative cells, increase of MHC class I expression was observed. This expression was lower than the expression of MHC class I molecule both in cultured MHC class I-positive cells and in ex vivo keratinocytes. Furthermore, stimulation of MHC class I-negative keratinocytes with interferon gamma (IFN-gamma) did not bring about further increase in MHC class I expression. MHC class I-negative cells were identified as keratinocytes as they expressed keratin 14 and formed keratinocyte colonies in vitro.
Matic
Maja
M
Department of Biochemistry, SUNY at Stony Brook, Stony Brook, NY 11794, USA. mmatic@notes.cc.sunysb.edu
D000078404:Epidermal Cells; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D006801:Humans; D053547:Keratin-14; D015603:Keratinocytes / Q000276:immunology*; D007633:Keratins / Q000378:metabolism; D008297:Male; D001613:beta 2-Microglobulin / Q000378:metabolism
D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; C507540:KRT14 protein, human; D053547:Keratin-14; D001613:beta 2-Microglobulin; D007633:Keratins