Langerhans' cells in the murine oral mucosa in the inductive phase of delayed type hypersensitivity with 1-chloro-2, 4-dinitrobenzene.

We created a murine model of delayed-type hypersensitivity (DTH) to 1-chloro-2, 4-dinitrobenzene (DNCB). Using this murine model, we compared oral mucosal sensitization and skin sensitization for the difference in reaction during the elicitation phase. Evaluation of sensitizability, using the mouse ear swelling test (MEST) after oral mucosal or skin sensitization, showed that the ear swelling response peaked 24 h after challenge. The optimal induction concentration was 1.0% in both oral mucosal and skin sensitization, resulting in a positive reaction rate of 100%. However, the ear swelling response 24 h after challenge with the optimal concentration of DNCB (1.0%) was significantly lower in oral mucosal than in skin sensitization. We compared the oral mucosal and skin sensitization sites for the number of Langerhans' cells (LC) and the antigen-presenting capability in the induction phase. The numbers of F4/80+ major histocompatibility complex (MHC) class II+ LC before induction did not differ significantly between the oral mucosa and the skin. After induction, F4/80+ MHC class II+ LC increased in number, but the increase was significantly smaller in the oral mucosa than in the skin. MEST on anti-CD86 antibody-administered mice showed that ear swelling was similarly suppressed after oral mucosal or skin sensitization. In murine models of DTH after oral mucosal sensitization, the number of F4/80+CD86+ LC increased after induction, but the increase was significantly smaller than that in murine models of DTH after skin sensitization. This study showed that, in murine models of DTH, oral mucosal sensitization elicited a weaker reaction than skin sensitization. This was presumably because oral mucosal sensitization induced fewer LC, resulting in lower antigen-presenting capability.