Highlights d Type I interferon drives differentiation of inf-cDC2s that closely resemble MCs d Inf-cDC2s prime CD4 + and CD8 + T cells, whereas MCs lack APC function d Inf-cDC2s internalize antibody-complexed antigen via Fc receptors d IRF8 controls maturation gene module in inf-cDC2s
The rodent hookworm Nippostrongylus brasiliensis typically infects its host by penetrating the skin and rapidly migrating to the lungs and gut. Following primary infection, immunocompetent mice become highly protected from reinfection with N. brasiliensis, with the numbers of worms gaining access to the lungs and gut being reduced by up to 90%. We used green fluorescent protein/interleukin-4 (IL-4) reporter mice and truncated infection studies to identify both the tissue site and mechanism(s) by which the host protects itself from reinfection with N. brasiliensis. Strikingly, we demonstrated that the lung is an important site for priming immune protection. Furthermore, a lung-initiated, CD4 T-cell-dependent, and IL-4-and STAT6-dependent response was sufficient to confer protection against reinfection. In conclusion, vaccination strategies which seek to break the cycle of reinfection and egg production by helminths such as hookworms can include strategies which directly stimulate Th2 responses in the lung.
Connor et al. show that transcriptomic profiling of DCs exposed to two different Th2 stimuli in vivo reveals large numbers of differentially expressed genes but few similarities between conditions.
Dendritic cells (DC) are critical for the initiation of immune responses; however, their role in priming IL-4–producing Th2 cells in vivo is not fully understood. We used a model of intradermal injection with fluorescent-labeled, nonviable larvae from the helminth parasite nonviable Nippostrongylus brasiliensis L3 larvae (Nb), a strong inducer of Th2 responses, together with IL-4–GFP reporter mice that enable a sensitive detection of IL-4 production to examine the contribution of DC to the priming of IL-4–producing CD4+ T cells in vivo. We found that parasite material is taken up by two distinct DC populations in draining lymph nodes: a mostly CD11cintMHC class II (MHCII)hiCD11b+Ly6C− dermal DC population and a CD11chiMHCIIintCD11b+Ly6C+ monocyte-derived DC population. After Nb treatment, these two DC populations appeared in the draining lymph nodes in comparable numbers and with similar kinetics; however, treatment with pertussis toxin blocked the migration of dermal DC and the priming of IL-4–producing T cells, but only partially affected monocyte-derived DC numbers. In line with this observation, transfer of OVA-loaded CD11cintMHCIIhi DC from Nb-treated mice into naive hosts could sensitize OVA-specific CD4+ T cells to IL-4 production, whereas transfer of CD11cintMHCIIhi DC from naive mice, or CD11chiMHCIIint DC from Nb-treated or naive mice, induced CD4+ T cell expansion but no IL-4 production. Phenotypic analysis of Nb-loaded CD11cintMHCIIhi DC revealed expression of programmed death ligand 2, CD301b, IFN regulatory factor 4, and moderate upregulation of OX40 ligand. However, thymic stromal lymphopoietin and OX40 ligand were not required for Th2 priming. Thus, our data suggest that appropriate stimuli can induce DC to express the unique signals sufficient to direct CD4+ T cells to Th2 differentiation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.