2B). Although the numbers of liver-infiltrating CD4 T cells were reduced in both the p40−/− and p35−/− mice compared to the dnTGFβRII mice (P < 0.01), the numbers of p35−/− CD8 T cells increased by 24 weeks and was significantly higher than in p40−/− or dnTGFβRII mice (P < 0.05) (Fig. 2B). The numbers of intrahepatic B cells, natural killer (NK) cells, and NKT cells were all significantly lower in p40−/− mice than dnTGFβRII mice

at both 12 and 24 weeks, whereas those of the p35−/− mice were in general intermediate between the other two mouse strains (data not shown). In summary, these results indicate that the absence of IL-12 p35 resulted in reduced liver inflammation at 12 weeks but not 24 weeks of age compared to dnTGFβRII mice. In contrast, deletion of the IL-12 p40 resulted in complete protection against liver inflammation and bile duct damage at Nutlin-3a mouse both 12 and 24 weeks. Liver fibrosis is characteristic of human PBC but has not been previously reported in murine models of PBC. To assess JNK activity the extent of fibrosis, Masson’s trichrome staining (Fig. 3B) and Sirius Red staining (Fig. 3D) were performed to detect collagen distribution. At 24 weeks

fibrosis was detected in 54% (7/13) of the p35−/− mice but none of 14 dnTGFβRII mice (P < 0.05, Fisher's exact test) (Fig. 3C). The results of liver fibrosis quantification with image analysis of Sirius Red staining sections further confirmed the presence of fibrosis in p35−/− mice (Fig. 3E). Mild

fibrosis was also observed in one out of eight p40−/− mice. However, the severity of fibrosis in this mouse was substantially lower than the p35−/− mice with fibrosis, based on the area of fibrosis Bupivacaine (Fig. 3C,E). The hepatic hydroxyproline content was significantly higher in p35−/− mice than p40−/− (P = 0.016) and dnTGFβRII mice (P = 0.007) at 24 weeks (Fig. 3F). To address the potential mechanism of fibrosis in IL-12p35−/− dnTGFβRII mice, we examined 84 genes associated with dysregulated wound healing, tissue repair, and remodeling in three groups using a PCR array. A total of 13 genes were significantly down-regulated in the IL-12p35−/−dnTGFβRII group (Table 1), including the important negative regulators in liver fibrosis STAT1, IFN-γ, and hepatocyte growth factor (HGF), suggesting that reduced expression levels of IFN-γ/STAT1 signaling and antifibrotic factor-HGF are involved in development of fibrosis in IL-12p35−/−dnTGFβRII mice. There were no significant differences in the level of serum AMAs among the three mice strains at 12 weeks. By 24 weeks, the serum AMA level was significantly higher in p35−/− mice compared to the other two strains (P < 0.05) (Fig. 4).