Inhibition of functional T cell priming and contact hypersensitivity responses by treatment with anti-secondary lymphoid chemokine antibody during hapten sensitization

Recent studies have suggested a pivotal role for secondary lymphoid chemokine (SLC) in directing dendritic cell trafficking from peripheral to lymphoid tissues. As an extension of these studies, we examined the consequences of anti-SLC Ab treatment during Ag priming on T cell function in an inflammatory response. We used a model of T cell-mediated inflammation, contact hypersensitivity (CHS), where priming of the effector T cells is dependent upon epidermal dendritic cell, Langerhans cells, and migration from the hapten sensitization site in the skin to draining lymph nodes. A single injection of anti-SLC Ab given at the time of sensitization with FITC inhibited Langerhans cell migration into draining lymph nodes for at least 3 days. The CHS response to hapten challenge was inhibited by anti-SLC Ab treatment in a dose-dependent manner. Despite the inhibition of CHS, T cells producing IFN-γ following in vitro stimulation with anti-CD3 mAb or with hapten-labeled cells were present in the skin-draining lymph nodes of mice treated with anti-SLC Ab during hapten sensitization. These T cells were unable, however, to passively transfer CHS to naive recipients. Animals treated with anti-SLC Ab during hapten sensitization were not tolerant to subsequent sensitization and challenge with the hapten. In addition, anti-SLC Ab did not inhibit CHS responses when given at the time of hapten challenge. These results indicate an important role for SLC during sensitization for CHS and suggest a strategy to circumvent functional T cell priming for inflammatory responses through administration of an Ab inhibiting dendritic cell trafficking.