Molecular regulation of Th2 immunity by dendritic cells.

The interactions between dendritic cells (DCs) and T cells determine the fate of an immune response to pathogenic microbes and to harmless allergens alike. The interactions between DCs and T cells is dependent on the maturation and differentiation status of DCs. This status is affected by the cellular lineage of the DCs and by signals that the cells receive from the environment and from T cells. A specific subpopulation of DCs (dendritic cell type 2 [DC2]) induces the development of T helper 2 (Th2) responses. Unregulated Th2 responses induce and cause inflammation in allergy and asthma. If it would be possible to target DC2 cells for prophylactic or therapeutic measures, then it may be possible to change the T cell response to allergens on a long-term basis. In the past few years, there have been major research efforts to elucidate molecular determinants of DC maturation. This review summarizes the new findings and their potential for future clinical application.