title: Langerhans' cells in equine cutaneous papillomas and normal skin.
abstract: Langerhans' cells (LC) were investigated immunohistochemically and electron microscopically in normal equine epidermis and 133 equine cutaneous papillomas experimentally induced in five 2-year-old Thoroughbred horses. Class II major histocompatibility complex antigen-positive dendritic LC were found in the normal epidermis and ultrastructurally had the characteristic Birbeck's granules. In the developing phase of the papillomas, LC were significantly decreased in number and size, indicative of a hypofunctional state. In the regressing phase of the papillomas, LC were markedly increased in number, especially at the epidermis-dermis junction. LC with long dendrites were rich in cytoplasm with well-developed cytoplasmic organelles, including Golgi apparatus, lysosomes, Birbeck's granules, and multivesicular bodies. These LC were hyperfunctional. An infiltration of many T lymphocytes was also observed at the epidermis-dermis junction.
authors.affiliation: Department of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Hamada
authors.forename: M
authors.initials: M
authors.lastname: Takechi
authors.forename: C
authors.initials: C
authors.lastname: Itakura
mesh_terms: D000818:Animals; D002455:Cell Division; D004817:Epidermis / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006734:Horse Diseases / Q000473:pathology*; D006736:Horses; D007150:Immunohistochemistry; D007801:Langerhans Cells / Q000737:chemistry / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D010212:Papilloma / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure / Q000662:veterinary*; D012878:Skin Neoplasms / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure / Q000662:veterinary*
chemical_list: D000949:Histocompatibility Antigens Class II