Early IL-17 production by intrahepatic T cells is important for adaptive immune responses in viral hepatitis.

ABSTRACT: This study was conducted to examine the interactions among the innate and adaptive immune components of the liver parenchyma during acute viral hepatitis. Mice were i.v. infected with a recombinant adenovirus, and within the first 24 h of infection, we found a transient but significant accumulation of IL-17 and IL-23 in the liver. In vivo neutralization of these interleukins alleviated the liver injury. Further investigations showed that IL-17 neutralization halted the intrahepatic accumulation of CTLs and Th1 cells. A majority of the IL-17-producing cells in the liver were ?? T cells. Additionally, intrahepatic IL-17(+) ?? T cells, but not the IFN-?(+) ones, preferentially expressed IL-7R? (CD127) on their surface, which coincided with an elevation of hepatocyte-derived IL-7 at 12 h postinfection. IL-7R? blockade in vivo severely impeded the expansion of IL-17-producing cells after viral infection. In vitro, IL-7 synergized with IL-23 and directly stimulated IL-17 production from ?? T cells in response to TCR?? stimulation. Finally, type I IFN (IFN-I) signaling was found to be critical for hepatic IL-7 induction. Collectively, these results showed that the IFN-I/IL-7/IL-17 cascade was important in priming T cell responses in the liver. Moreover, the highly coordinated cross talk among hepatocytes and innate and adaptive immune cells played a critical role in anti-viral immunity in hepatitis.

SUBMITTER: Hou L 

PROVIDER: S-EPMC3538895 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature