Human Dendritic Cells with Th2-Polarizing Capacity: Analysis Using Label-Free Quantitative Proteomics

Dendritic cells (DCs) are the sentinels of the immune system. Upon recognition of a pathogen, they mature and migrate to draining lymph nodes to prime and polarize T cell responses. Although it is known that helminths and helminth-derived molecules condition DCs to polarize T helper (Th) cells towards Th2, the underlying mechanisms remain incompletely understood.

The aim of this study was to conduct a proteome analysis of helminth antigen-stimulated DCs in order to gain more insight into the cellular processes associated with their ability to polarize immune responses.

We analyzed the maturation and polarization of monocyte-derived DCs from 9 donors at 2 different time points after stimulation with different Th1- and Th2-polarizing pathogen-derived molecules. The samples were measured using liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry for relative quantitation.

Lipopolysaccharide-induced maturation promoted the expression of proteins related to metabolic, cellular, and immune system processes. Th1-polarizing DCs, conditioned by IFN-γ during maturation, displayed accelerated maturation by differentially expressing cytoskeletal proteins and proteins involved in immune regulation. The stimulation of DCs with soluble egg antigens and omega-1 derived from Schistosoma mansoni, which are both Th2-inducing stimuli, increased 60S acidic ribosomal protein P2, and vesicle amine transferase 1 while decreasing the expression of proteins related to antigen processing and presentation.

Our data indicate that not only proteins involved in the interaction between T cells and DCs at the level of the immunological synapse, but also those related to cellular metabolism and stress, may promote Th2 polarization.