Type I interferon is required for T helper (Th) 2 induction by dendritic cells.

Type 2 inflammation is a defining feature of infection with parasitic worms (helminths), as well as being responsible for widespread suffering in allergies. However, the precise mechanisms involved in T helper (Th) 2 polarization by dendritic cells (DCs) are currently unclear. We have identified a previously unrecognized role for type I IFN (IFN-I) in enabling this process. An IFN-I signature was evident in DCs responding to the helminth Schistosoma mansoni or the allergen house dust mite (HDM). Further, IFN-I signaling was required for optimal DC phenotypic activation in response to helminth antigen (Ag), and efficient migration to, and localization with, T cells in the draining lymph node (dLN). Importantly, DCs generated from Ifnar1-/- mice were incapable of initiating Th2 responses in vivo These data demonstrate for the first time that the influence of IFN-I is not limited to antiviral or bacterial settings but also has a central role to play in DC initiation of Th2 responses.

Genetic screens to study the immune system in cancer.

RNA interference and CRISPR/Cas9 technologies now enable systematic discovery of genes that regulate key pathways in the complex interaction between immune cells and tumor cells. Discovery screens are feasible in an in vivo setting, allowing identification of genes that limit the effectiveness of anti-tumor immunity. In vivo discovery screens can be informed by single-cell RNA-seq experiments that define the differentially expressed genes between functionally distinct immune cell subpopulations, both in humans and relevant animal models. Novel targets for cancer immunotherapy are being defined by the in depth functional annotation of immunosuppressive pathways in the tumor microenvironment.