RT Journal Article ID 6a7ff69a05d33a05 A1 Frasca, Loredana A1 Piazza, Cinzia A1 Piccolella, Enza T1 CD4+ T Cells Orchestrate Both Amplification and Deletion of CD8+T Cells JF Critical Reviews™ in Immunology JO CRI YR 1998 FD 1998-12-20 VO 18 IS 6 SP 569 OP 594 K1 activation K1 tolerance K1 anergy K1 apoptosis K1 Fas/FasL interaction. AB This review focuses on the role of CD4+ T cells in regulating immune responses, orchestrating both the amplification and deletion of immune cells, particularly CD8+ T cells. These two functions, which represent only an apparent contradiction, appear to be two faces of the same process of regulation. In fact, because the immune response, once activated, needs to be carefully controlled or switched off when the antigenic stimulus is eliminated, the immune system has developed several strategies either to regulate clonal amplification or to avoid useless expansion of activated cells. In particular, we have reported many data demonstrating that CD4+ T cells may be indicated as the regulatory element in the activation as well as the deletion of CD8+T cells. New data are also reported on the ability of anergic CD4+ T cells to suppress CD8+ T-cell activation through induction of apoptosis, and on the need for CD8+ T cells for antigen recognition in inducing cell death in CD4+ T cells. Moreover, the central role of CD4+ T cells in the maintenance of peripheral tolerance has been widely described. PB Begell House LK https://www.dl.begellhouse.com/journals/2ff21abf44b19838,390d3fc461d10f95,6a7ff69a05d33a05.html