[HTML][HTML] Type I IFN signaling in CD8 DCs impairs Th1-dependent malaria immunity

A Haque, SE Best, MM De Oca… - The Journal of …, 2014 - Am Soc Clin Investig
A Haque, SE Best, MM De Oca, KR James, A Ammerdorffer, CL Edwards…
The Journal of clinical investigation, 2014Am Soc Clin Investig
Many pathogens, including viruses, bacteria, and protozoan parasites, suppress cellular
immune responses through activation of type I IFN signaling. Recent evidence suggests that
immune suppression and susceptibility to the malaria parasite, Plasmodium, is mediated by
type I IFN; however, it is unclear how type I IFN suppresses immunity to blood-stage
Plasmodium parasites. During experimental severe malaria, CD4+ Th cell responses are
suppressed, and conventional DC (cDC) function is curtailed through unknown …
Many pathogens, including viruses, bacteria, and protozoan parasites, suppress cellular immune responses through activation of type I IFN signaling. Recent evidence suggests that immune suppression and susceptibility to the malaria parasite, Plasmodium, is mediated by type I IFN; however, it is unclear how type I IFN suppresses immunity to blood-stage Plasmodium parasites. During experimental severe malaria, CD4+ Th cell responses are suppressed, and conventional DC (cDC) function is curtailed through unknown mechanisms. Here, we tested the hypothesis that type I IFN signaling directly impairs cDC function during Plasmodium infection in mice. Using cDC-specific IFNAR1-deficient mice, and mixed BM chimeras, we found that type I IFN signaling directly affects cDC function, limiting the ability of cDCs to prime IFN-γ–producing Th1 cells. Although type I IFN signaling modulated all subsets of splenic cDCs, CD8 cDCs were especially susceptible, exhibiting reduced phagocytic and Th1-promoting properties in response to type I IFNs. Additionally, rapid and systemic IFN-α production in response to Plasmodium infection required type I IFN signaling in cDCs themselves, revealing their contribution to a feed-forward cytokine-signaling loop. Together, these data suggest abrogation of type I IFN signaling in CD8 splenic cDCs as an approach for enhancing Th1 responses against Plasmodium and other type I IFN–inducing pathogens.
The Journal of Clinical Investigation