Anisakis pegreffii impacts differentiation and function of human dendritic cells

Summary Human dendritic cells ( DC s) show remarkable phenotypic changes when matured in the presence of helminth‐derived products. These modifications frequently elicited a polarization towards Th2 cells and regulatory T cells thus contributing to immunological tolerance against these pathogens. In this study, the interaction between DC s and larvae of the zoonotic anisakid nematode Anisakis pegreffii was investigated. A. pegreffii larvae were collected from fish hosts, and monocyte‐derived DC s were cocultured in the presence of the live larvae (L) or its crude extracts ( CE ). In both experimental conditions, A. pegreffii impacted DC viability, hampered DC maturation by reducing the expression of molecules involved in antigen presentation and migration (ie HLA ‐ DR , CD 86, CD 83 and CCR 7), increased the phagosomal radical oxygen species ( ROS ) levels and modulated the phosphorylation of ERK 1,2 pathway. These biological changes were accompanied by the impairment of DC s to activate a T‐cell‐mediated IFN γ. Interestingly, live larvae appeared to differently modulate DC secretion of cytokines and chemokines as compared to CE . These results demonstrate, for the first time, the immunomodulatory role of A. pegreffii on DC s biology and functions. In addition, they suggest a dynamic contribution of DC s to the induction and maintenance of the inflammatory response against A. pegreffii .