Role of dendritic cell-derived cytokines in immune regulation.

Over the last several years, it has become increasingly clear that dendritic cells (DC) are not only critical for the initiation of T cell immunity, but these cells also determine the course of the subsequent immune response (i.e. tolerance vs. immunity, Th1 vs. Th2). However, the mechanisms by which DC can influence the final outcome of a given immune response remain to be understood. Currently, the ability of DC to direct immunity has been linked to: (1) hematopoeitic lineage, (2) maturation stage, and (3) environmental stimuli. While the literature supports each possibility, one common feature of all three hypotheses is that immunological outcome is directly correlated to the profile of DC-derived cytokines. A review of the existing scientific literature strongly suggests that the capacity of DC to orchestrate the immune responses is not an intrinsic quality of the cell, but rather it is the result of environmental stimulation which is reflected in their cytokine and chemokine production.