CD4+ T cell-targeted immunomodulation and the therapy of allergic disease

In recent years there have been considerable advances in our knowledge of the cellular and molecular events following ligation of the T cell receptor. The quantitative and qualitative characteristics of the signal(s) received by a naive or memory T cell largely determine whether receptor ligation results in cell activation, cell death, or the induction of a state of antigen-specific nonresponsiveness. Furthermore, microenvironmental conditions, including the presence of secreted cytokines or the structure of the peptide antigen, strongly influence the differentiation of CD4+ helper cells into functionally distinct subsets. The interregulation of these functional subsets appears pivotal to the development of many immune-mediated disorders, including allergic disease. We suggest that the selective manipulation of the immune response to specific antigens may be an effective strategy for the therapy of such disorders and we review recent studies which support this concept.