Regulatory role of CD4+ T cells during the development of contact hypersensitivity responses.

Contact hypersensitivity (CHS) is a T cell-mediated immune response to cutaneous sensitization and subsequent challenge with haptens such as dinitrofluorobenzene and oxazolone. Many aspects concerning the development and regulation of CHS remain unknown. Using CHS as a model of T cell-mediated immune responses to antigens deposited in the skin we have studied the development and function of effector and regulatory T cell components of this response. These studies have revealed the effector role of hapten-specific CD8+ T cells in this response. In contrast, hapten-specific CD4+ T cells negatively regulate the magnitude and duration of the response. In this article we propose a model in which the CD4+ T cell compartment regulates the development of effector CD8+ T cells during sensitization for CHS and discuss potential mechanisms that CD4+ T cells might utilize to mediate this regulation.