| First Author | Trevejo-Nunez G | Year | 2016 |
| Journal | J Immunol | Volume | 197 |
| Issue | 5 | Pages | 1877-83 |
| PubMed ID | 27456484 | Mgi Jnum | J:266729 |
| Mgi Id | MGI:6256930 | Doi | 10.4049/jimmunol.1600528 |
| Citation | Trevejo-Nunez G, et al. (2016) Critical Role of IL-22/IL22-RA1 Signaling in Pneumococcal Pneumonia. J Immunol 197(5):1877-83 |
| abstractText | IL-22-IL-22R signaling plays a crucial role in regulating host defenses against extracellular pathogens, particularly in the intestine, through the induction of antimicrobial peptides and chemotactic genes. However, the role of IL-22-IL-22R is understudied in Streptococcus pneumoniae lung infection, a prevalent pathogen of pneumonia. This paper presents the findings of IL-22 signaling during a murine model of pneumococcal pneumonia and improvement of bacterial burden upon IL-22 administration. IL-22 was rapidly induced in the lung during pneumococcal infection in wild-type mice, and Il22(-/-) mice had higher pneumococcal burdens compared with controls. Additionally, mice with hepatic-specific deletion of Il22ra1 also had higher bacterial burdens in lungs compared with littermate controls after intrapulmonary pneumococcal infection, suggesting that IL-22 signaling in the liver is important to control pneumococcal pneumonia. Thus, we hypothesized that enhancement of IL-22 signaling would control pneumococcal burden in lung tissues in an experimental pneumonia model. Administration of rIL-22 systemically to infected wild-type mice decreased bacterial burden in lung and liver at 24 h postinfection. Our in vitro studies also showed that mice treated with IL-22 had increased C3 expression in the liver compared with the isotype control group. Furthermore, serum from mice treated with IL-22 had improved opsonic capacity by increasing C3 binding on S. pneumoniae Taken together, endogenous IL-22 and hepatic IL-22R signaling play critical roles in controlling pneumococcal lung burden, and systemic IL-22 decreases bacterial burden in the lungs and peripheral organs by potentiating C3 opsonization on bacterial surfaces, through the increase of hepatic C3 expression. |
