| First Author | Reiman RM | Year | 2006 |
| Journal | Infect Immun | Volume | 74 |
| Issue | 3 | Pages | 1471-9 |
| PubMed ID | 16495517 | Mgi Jnum | J:107418 |
| Mgi Id | MGI:3621106 | Doi | 10.1128/IAI.74.3.1471-1479.2006 |
| Citation | Reiman RM, et al. (2006) Interleukin-5 (IL-5) augments the progression of liver fibrosis by regulating IL-13 activity. Infect Immun 74(3):1471-9 |
| abstractText | Eosinophils are frequently found in increased numbers in a variety of chronic fibrotic diseases; however, their role in the development of hepatic fibrosis has not been dissected in vivo. Here, we used interleukin-5 (IL-5) knockout (KO) mice to determine whether eosinophils contribute to the progressive liver fibrosis that develops in response to chronic Schistosoma mansoni infection. Although infection intensities were similar in C57BL/6 and IL-5 KO mice, the average size of granulomas was significantly smaller in both acutely and chronically infected IL-5 KO mice. Their granulomas were also completely devoid of eosinophils. In addition, the knockout mice displayed over a 40% reduction in hepatic fibrosis by week 16 postinfection. The reduced fibrosis was associated with increased production of the antifibrotic cytokine gamma interferon. Moreover, although IL-13 production did not decrease consistently in the absence of IL-5, IL-13-triggered responses were substantially reduced in the granulomatous tissues. This was confirmed by analyzing the expression of several genes associated with alternative macrophage activation, including arginase 1, Fizz-1, and YM-1. Importantly, all of these IL-13-regulated genes have been linked with the mechanisms of wound healing and fibrosis. In addition to IL-5 polarizing the antigen-specific CD4+ Th2 cell response, we found that granuloma eosinophils were themselves a significant source of IL-13. Thus, by producing profibrotic mediators and polarizing the Th2 response, these findings illustrate both direct and indirect roles for eosinophils and IL-5 in the pathogenesis of schistosomiasis-induced liver fibrosis. Thus, inhibiting the activity of IL-5 or eosinophils may prove effective for a variety of chronic fibrotic diseases. |
