title: Ultrastructural analysis of MHC class II molecule-expressing cells in experimentally induced periapical lesions in the rat.
abstract: Periapical lesions were induced by making 28 days of unsealed pulp exposures in the lower first molars of Wistar rats. Major histocompatibility complex class II molecule-expressing cells were then demonstrated by means of immunoperoxidase staining using a monoclonal antibody OX6, and the ultrastructure of these cells was analyzed under electron microscopy. OX6+ cells were classified into two major populations, (i.e. macrophages and dendritic cell (DC)-like cells. DC-like cells had elongated cytoplasmic processes, contained a few lysosomal structures, lacked distinct phagosomes, and were the most predominant cell type in the established lesion. Some of lymphocytes and plasma cells also showed a positive immunoreactivity. Both OX6+ macrophages and DC-like cells often showed a cell-to-cell attachment with lymphocytes. These findings suggested that major histocompatibility complex class 11 molecule-expressing macrophages and DC-like cells may play a crucial role in periapical lesion development by acting as antigen-presenting cells to memory T lymphocytes.
authors.affiliation: Department of Restorative Science, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kaneko
authors.forename: T
authors.initials: T
authors.lastname: Okiji
authors.forename: L
authors.initials: L
authors.lastname: Kan
authors.forename: M
authors.initials: M
authors.lastname: Takagi
authors.forename: H
authors.initials: H
authors.lastname: Suda
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D003713:Dendritic Cells / Q000276:immunology / Q000648:ultrastructure*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D007124:Immunoenzyme Techniques; D008264:Macrophages / Q000276:immunology / Q000648:ultrastructure*; D008297:Male; D010482:Periapical Abscess / Q000276:immunology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II