Induction and regulation of T-cell priming for contact hypersensitivity

Contact hypersensitivity (CHS) is a T-cell-mediated immune response to cutaneous sensitization and subsequent challenge with haptens such as dinitrofluorobenzene and oxazolone. Clinically, contact sensitivity, also called allergic contact dermatitis, is a frequently observed dermatosis in industrialized countries. Experimental CHS in mice has been used by many laboratories as a model of T-cell-mediated immune responses to antigens deposited onto the skin to study the priming, development, and function of effector and regulatory T-cell components during these responses. In this article we discuss the mechanism of T-cell priming by hapten-presenting Langerhans cells and how the priming environment influences the development of these hapten-specific T cells to different functional phenotypes during sensitization for the CHS response. Finally, we propose a model of negative regulation of the CHS response by T-cell components that are coincidentally primed with the effector T cells mediating the response. Overall, these aspects indicate a unique immune response mediated and regulated by specialized antigen-presenting cells and T-cell populations.