Distinct dendritic cell subsets actively induce Th2 polarization

The mechanisms by which dendritic cells induce Th2 polarization (DCTh2 cells) have been controversial. Many have argued that DCTh2 cells are not a distinct functional DC subset, but rather, DC-induced polarization of Th2 cells is a default pathway that occurs in the absence of inflammatory signals leading to DC-induced polarization of Th1/Th17 cells. However, recent studies demonstrate that distinct subsets of tissue DCs actively polarize Th2 cells after stimulation with type-2 inducing stimuli. DCTh2 cells development is marked by the upregulation of specific transcription factors, cell surface molecules, and cytokines. These findings counter previous hypotheses that Th2 skewing by DCs is a passive response and support a model in which DCs are actively programmed to induce Th2 differentiation.