Chemokines and chemokine receptors in T-cell priming and Th1/Th2- mediated responses

T-cell priming occurs in the lymphoid tissue via T cell-dendritic cell interaction. Conversely, delayed-type hypersensitivity or allergic reactions can occur in any tissue, following interaction of T helper 1 (Th1) or Th2 cells with effector leukocytes. Here, Federica Sallusto and colleagues review the role played by chemokines and chemokine receptors in positioning T cells for the immune response.