Structure and Probable Functional Role of the Nasopharyngeal Lymphoepithelial Tissue of the Mouse

Abstract

Summary: The “nasopharyngeal lymphoepithelial tissue” (named by the authors) was located in the dorsal and lateral walls of the mouse nasopharynx, and consisted of the lymphoepithelium and the underlying lymphoid aggregation. The lymphoepithelium showed gradations ranging from columnar to squamous type and was occasionally ciliated. It was heavily infiltrated by the underlying lymphoid cells and could not be established its deep border. Although no typical crypts were observed, the lymphoepithelium showed prominent surface discontinuities to allow the lymphoid cells to come in contact with the external environment. Some of the epithelial cells showed many surface pits suggesting micropinocytosis. It was considered that the nasopharyngeal lymphoepithelial tissue corresponded to the human pharyngeal tonsil and played an important role in defense of the inlet of the lower respiratory tract.