CD8+ T lymphocyte response against extrahepatic biliary epithelium is activated by epitopes within NSP4 in experimental biliary atresia.

Interferon (IFN)-γ-driven and CD8+ T cell-dependent inflammatory injury to extrahepatic biliary epithelium (EHBE) is likely to be involved in the development of biliary atresia (BA). We previously showed that viral protein NSP4 is the pathogenic immunogen that causes biliary injury in BA. In this study, NSP4 or four synthetic NSP4 (NSP4(157-170), NSP4(144-152), NSP4(93-110), NSP4(24-32)) identified by computer analysis as candidate CD8+ T cell epitopes were injected into neonatal mice. The pathogenic NSP4 epitopes were confirmed by studying extrahepatic bile duct injury, IFN-γ release and CD8+ T cell response against EHBE. The results revealed, at 7 days postinjection, inoculation of glutathione S-transferase (GST)-NSP4 caused EHBE injury and BA in neonatal mice. At 7 or 14 days postinject, inoculation of GST-NSP4, NSP4(144-152), or NSP4(157-170) increased IFN-γ release by CD8+ T cells, elevated the population of hepatic memory CD8+ T cells, and augmented cytotoxicity of CD8+ T cells to rhesus rotavirus (RRV)-infected or naive EHBE cells. Furthermore, depletion of CD8+ T cells in mice abrogated the elevation of GST-NSP4-induced serum IFN-γ. Lastly, parenteral immunization of mouse dams with GST-NSP4, NSP4(144-152), or NSP4(157-170) decreased the incidence of RRV-induced BA in their offspring. Overall, this study reports the CD8+ T cell response against EHBE is activated by epitopes within rotavirus NSP4 in experimental BA. Neonatal passive immunization by maternal vaccination against NSP4(144-152) or NSP4(157-170) is effective in protecting neonates from developing RRV-related BA.

Decreasing rate of biliary atresia in Taiwan: a survey, 2004-2009.

OBJECTIVES: The pathogenesis of biliary atresia (BA) is unclear, but epidemiological studies may help to elucidate possible causes. The goals of this study were to identify BA incidence changes in Taiwan in 2004-2009 and to survey the factors that might influence incidence changes to elucidate the possible causes of BA. METHODS: A Taiwan national registry system for BA has been established since 2004. By using data from the national registry system for BA, we identified BA incidence changes in 2004-2009. We also evaluated the correlations between BA incidences and estimated rotavirus vaccine coverage rates and between BA incidences and the gross domestic product. RESULTS: A total of 185 patients with BA were identified in 2004-2009 in Taiwan, whereas the number of live births was 1 221 189. Compared with the incidence of BA in 2004-2006 (1.79 cases per 10,000 live births), the incidence of BA in 2007-2009 (1.23 cases per 10,000 live births) was decreased significantly (P = .01). BA incidences were negatively correlated with the gross domestic product (P = .02) and marginally negatively correlated with rotavirus vaccine coverage rates (P = .07). CONCLUSIONS: A significant decrease in BA incidence in Taiwan since 2007 has been noted and may be related to improvements in the general socioeconomic status and the popularity of rotavirus vaccination. Although more evidence is needed to establish a direct correlation, this phenomenon may shed light on possible causes of and preventive interventions for BA.

Preconceptional oral vaccination prevents experimental biliary atresia in newborn mice.

INTRODUCTION: Biliary atresia (BA) in humans resembles BA induced in Balb/c-mice by Rhesus Rotavirus (RRV). In mice, susceptibility to BA is ascribed to the lack of maternally derived immune protection. This study investigated whether vaccination of dams against RRV protected their offspring from developing BA. MATERIALS AND METHODS: Before mating, female mice were vaccinated orally with RotaTeq or Rotarix. Pups (n=243) from both test groups and a control group were intraperitoneally infected with RRV. Sacrifice of the animals was scheduled for days 7, 14 and 21 after infection. Then, gross and mircoscopia findings of the liver and the hepatoduodenal ligament gave evidence of BA, and hepatic viral load was tested by virus-specific real-time PCR, as well as plaque forming units. RESULTS: Two weeks after infection, the incidence of cholestasis was 100% in controls, 77% in pups of RotaTeq-vaccinated dams, and 56% in pups of Rotarix-vaccinated dams. However, in contrast to controls (incidence of BA: 82%) most pups in the test groups recovered (incidence of BA in pups of RotaTeq-vaccinated dams 11%; incidence of BA in pups of Rotarix-vaccinated dams 3%). Hepatic viral load was identical at various time-points in all pups, suggesting that differences in RRV clearance did not underlie this effect. CONCLUSION: In this mouse model, oral vaccination with RotaTeq and Rotarix prevented most RRV-induced BA. This provides a new approach to a better understanding of both the pathomechanism of BA development and the capabilities of the innate immune system. It also suggests a first approach for prophylaxis against BA.

Prevention of the murine model of biliary atresia after live rotavirus vaccination of dams.

PURPOSE: Biliary atresia (BA) is a neonatal disease that results in the obliteration of the biliary tree. The murine model of BA has been established where rhesus rotavirus (RRV) infection of newborn mice leads to an obstructive cholangiopathy. We determined whether maternal postconception rotavirus vaccination could prevent the murine model of BA. MATERIALS AND METHODS: Female mice were mated and injected intraperitoneally with one of the following materials: purified rotavirus strains RRV or Wa, high or low-dose Rotateq (Merck and Co Inc, Whitehouse Station, NJ) (a pentavalent rotavirus vaccine [PRV]), purified recombinant viral antigens of rotavirus (VP6) or influenza (NP), or saline. B-cell-deficient females also underwent postconception PRV injection. RESULTS: Maternal vaccination with PRV improves survival of pups infected with RRV. Serum rotavirus IgG, but not IgA, levels were increased in pups delivered from dams who received RRV, Wa, PRV, or VP6, but in the case of the Wa, PRV, and VP6 groups, these antibodies were not neutralizing. Postconception injection of high-dose PRV did not improve survival of pups born to B-cell-deficient dams. CONCLUSION: Maternal vaccination against RRV can prevent the rotavirus-induced murine model of BA in newborn mouse pups.

Functional Mx protein does not prevent experimental biliary atresia in Balb/c mice.

Biliary atresia (BA) is a rare cholestatic disease, which manifests itself in the form of inflammation of the liver and bile ducts in newborns, with an unknown etiology and a poor outcome. Mx proteins, which are mediators of innate, antiviral resistance induced by type I interferon, were recently detected in the livers of children with BA. Therefore, the aim of this study was to examine whether the expression of Mx protein could affect the course of experimental BA in mice. A total of 185 newborn Balb/c mice (expressing dysfunctional Mx protein) and Balb/c-Mx+-A2G mice (with functional Mx protein) were intraperitoneally infected with rhesus rotavirus (RRV) or injected with saline solution as controls. They were sacrificed if they showed signs of cholestasis or at three weeks after infection. The expression of hepatic Mx protein was detected by immunostaining (POX) and the hepatic virus load was determined. There was no significant difference in the incidence of cholestasis between wild-type Balb/c mice and Balb/c-Mx+-A2G mice (67 % vs. 65 %). However, Mx protein was highly expressed in Balb/c-Mx+-A2G mice with BA phenotype, but not in wild type Balb/c mice or disease-free Balb/c-Mx+-A2G mice despite RRV infection. The difference in the hepatic virus load was not statistically significant in mice with BA. In conclusion, Mx protein does not prevent newborn Balb/c mice from developing biliary atresia after RRV infection. However, the expression of Mx protein is independent of the hepatic virus load and could be used as a marker of BA in humans, as well as in the RRV model.