Immunohistochemical characterization and localization of MHC class II antigen-presenting cells in the periodontal ligament of rat incisors.

Dendritic cells have been identified both in lymphoid and nonlymphoid tissues as non-phagocytic antigen-presenting cells, equipped with extensive flamelike cytoplasmic projections. Our immunohistochemical study revealed presence of a large population of dendritic cells and other immunocompetent cells, showing a region-specific distribution, in the lingual periodontal ligament of continuously erupting rat incisors. This study aims to reveal the kinetics and cytological characterization of immunocompetent cells in the periodontal ligament of rat incisors with special reference to their differentiation pathway in the unique local environment.