Human embryonic epidermis contains a diverse Langerhans cell precursor pool.
Despite intense efforts, the exact phenotype of the epidermal Langerhans cell (LC) precursors during human ontogeny has not been determined yet. These elusive precursors are believed to migrate into the embryonic skin and to express primitive surface markers, including CD36, but not typical LC markers such as CD1a, CD1c and CD207. The aim of this study was to further characterize the phenotype of LC precursors in human embryonic epidermis and to compare it with that of LCs in healthy adult skin. We found that epidermal leukocytes in first trimester human skin are negative for CD34 and heterogeneous with regard to the expression of CD1c, CD14 and CD36, thus contrasting the phenotypic uniformity of epidermal LCs in adult skin. These data indicate that LC precursors colonize the developing epidermis in an undifferentiated state, where they acquire the definitive LC marker profile with time. Using a human three-dimensional full-thickness skin model to mimic in vivo LC development, we found that FACS-sorted, CD207(-) cord blood-derived haematopoietic precursor cells resembling foetal LC precursors but not CD14(+)CD16(-) blood monocytes integrate into skin equivalents, and without additional exogenous cytokines give rise to cells that morphologically and phenotypically resemble LCs. Overall, it appears that CD14(-) haematopoietic precursors possess a much higher differentiation potential than CD14(+) precursor cells.
Department of Dermatology, Division of Immunology, Allergy and Infectious Diseases (DIAID), Laboratory of Cellular and Molecular Immunobiology of the Skin, Medical University of Vienna, Vienna, Austria.
Christopher
C
Schuster
Michael
M
Mildner
Mario
M
Mairhofer
Wolfgang
W
Bauer
Christian
C
Fiala
Marion
M
Prior
Wolfgang
W
Eppel
Andrea
A
Kolbus
Erwin
E
Tschachler
Georg
G
Stingl
Adelheid
A
Elbe-Bürger
D018952:Antigens, CD34 / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000196:embryology*; D005312:Fetal Blood / Q000166:cytology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D007150:Immunohistochemistry; D007801:Langerhans Cells / Q000166:cytology*; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008954:Models, Biological; D010641:Phenotype; D018709:Statistics, Nonparametric; D046509:Tissue Culture Techniques
D018952:Antigens, CD34; D018950:Lipopolysaccharide Receptors
Development; Langerhans cell; Precursor; Skin; Skin equivalent