Differential cytokeratin and glycoconjugate expression by the surface and crypt epithelia of human palatine tonsils

Human palatine tonsils are clinically important due to their susceptibility to tonsillitis and association with other local and systemic diseases. Par adoxically, the tonsils function as antigen sampling sites of the mucosal i mmune system and, consequently, the tonsil epithelia perform both protectiv e and antigen sampling roles. These epithelia are divided into stratified s quamous epithelium overlying the tonsil surface and crypt epithelium lining the tonsil crypts, the latter of which includes reticular areas which are infiltrated by lymphocytes and are responsible for antigen sampling. In thi s study we characterised cytokeratin and glycoconjugate expression by healt hy epithelia of human palatine tonsils. We identified pan-epithelial tonsil markers and also demonstrated that the surface and reticular crypt epithel ia are differentiated by the expression of multiple cytokeratins. The latte r finding supports the hypothesis that these epithelia undergo alternate di fferentiation pathways and possess different functional roles. In addition, we identified cell subpopulations in the tonsil epithelia which may repres ent distinct cell subtypes including specialised antigen sampling cells. Th ese findings establish a basis for future studies to investigate histochemi cal changes in tonsil epithelia that are associated with or predispose to l ocal and/or systemic disease.