Frasca L, Piazza C, Piccolella E
Department of Cellular and Developmental Biology, La Sapienza University of Rome, Italy.
Crit Rev Immunol. 1998;18(6):569-94. doi: 10.1615/critrevimmunol.v18.i6.50.
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.
本综述聚焦于CD4+ T细胞在调节免疫反应中的作用，其协调免疫细胞（尤其是CD8+ T细胞）的扩增和清除。这两种功能看似矛盾，实则是同一调节过程的两个方面。事实上，由于免疫反应一旦激活，在抗原刺激消除时就需要仔细控制或关闭，免疫系统已发展出多种策略来调节克隆扩增或避免活化细胞的无用扩增。特别是，我们已报道了许多数据，表明CD4+ T细胞可能是CD8+ T细胞激活及清除过程中的调节因素。还报道了新的数据，即无反应性CD4+ T细胞通过诱导凋亡来抑制CD8+ T细胞激活的能力，以及CD8+ T细胞在诱导CD4+ T细胞死亡中进行抗原识别的必要性。此外，CD4+ T细胞在维持外周免疫耐受中的核心作用已得到广泛描述。
