An animal model for human hepatitis B virus (HBV) tolerance is needed to investigate the mechanisms. This model will also facilitate therapeutic strategies for the existing 350 million patients with chronic hepatitis B. We established a mouse model by hydrodynamic injection of an engineered, replication-competent HBV DNA into the tail veins of C57BL͞6 mice. In 40% of the injected mice, HBV surface antigenemia persisted for >6 months. Viral replication intermediates, transcripts, and proteins were detected in the liver tissues of the injected mice for up to 1 year. The tolerance toward HBV surface antigen in this model was shown to be due to an insufficient cellular immunity against hepatitis B core antigen, as was documented in humans. This animal model will accelerate further genetic and mechanistic studies of human chronic hepatitis B infection.surface antigen tolerance ͉ hydrodynamic injection ͉ DNA ͉ HBV persistence H epatitis B virus (HBV) is a noncytopathic, enveloped virus with a circular, double-stranded DNA genome. It causes acute and chronic necroinflammatory liver diseases and, subsequently, hepatic cirrhosis and hepatocellular carcinoma. Although a highly effective preventive vaccine is now available, it does not help the estimated 350 million people who have already been infected chronically and are at risk of developing end-stage liver disease and hepatocellular carcinoma.Although the chronicity of HBV infection is the result of impaired HBV-specific immune responses that cannot eliminate or cure the infected hepatocytes efficiently, many issues remained unsettled (1). It is thus crucial to the advancement of our understanding to have a suitable laboratory animal to study the immunopathogenesis of HBV infection and the mechanisms of HBV persistence. The mouse is the most suitable laboratory animal for immunological studies; however, it cannot be infected with HBV. Thus, most of the studies on immunopathogenesis of HBV have been approached by using HBV-transgenic mice which are inherently tolerant to transgene products (2-5). In these models, manipulation of the animals that are not in normal physiological conditions is required. Thus, many researchers attempted to establish an HBV model in nontransgenic mice. So far, only acute hepatitis B can be demonstrated by using these models (6, 7). These existing animal models have provided invaluable information on the mechanisms of immunopathogenesis of hepatitis B. However, they have limitations in addressing what happens at the onset of HBV infection that determines HBV persistence. Therefore, a mouse model of HBV persistence enabling scientists to study the mechanisms of HBV chronicity is desperately needed.To meet this challenge, we created a nontransgenic model of persistent HBV infection in immunocompetent mice. We took advantage of the liver-targeting manner of hydrodynamic injection (8). A single hydrodynamic injection of a replication-competent HBV DNA, pAAV͞HBV1.2, into mice could result in HBV persistence for Ͼ1 year in a significant proportion ...

Chronic infection is difficult to overcome because of exhaustion or depletion of cytotoxic effector CD8(+) T cells (cytotoxic T lymphoytes (CTLs)). Here we report that signaling via Toll-like receptors (TLRs) induced intrahepatic aggregates of myeloid cells that enabled the population expansion of CTLs (iMATEs: 'intrahepatic myeloid-cell aggregates for T cell population expansion') without causing immunopathology. In the liver, CTL proliferation was restricted to iMATEs that were composed of inflammatory monocyte-derived CD11b(+) cells. Signaling via tumor-necrosis factor (TNF) caused iMATE formation that facilitated costimulation dependent on the receptor OX40 for expansion of the CTL population. The iMATEs arose during acute viral infection but were absent during chronic viral infection, yet they were still induced by TLR signaling. Such hepatic expansion of the CTL population controlled chronic viral infection of the liver after vaccination with DNA. Thus, iMATEs are dynamic structures that overcome regulatory cues that limit the population expansion of CTLs during chronic infection and can be used in new therapeutic vaccination strategies.

T cells with a CAR specific for HBV envelope proteins localize to the liver in mice to reduce HBV replication, causing only transient liver damage. This immune cell therapy might be developed for patients with chronic hepatitis B, regardless of their HLA type.

Immunotherapy aiming to rescue or boost antitumor immunity is an emerging strategy for treatment of cancers. The efficacy of immunotherapy is strongly controlled by the immunological milieu of cancer patients. Myeloid-derived suppressor cells (MDSCs) are heterogeneous immature myeloid cell populations with immunosuppressive functions accumulating in individuals during tumor progression. The signaling mechanisms of MDSC activation have been well studied. However, there is little known about the metabolic status of MDSCs and the physiological role of their metabolic reprogramming. In this study, we discovered that myeloid cells upregulated their glycolytic genes when encountered with tumor-derived factors. MDSCs exhibited higher glycolytic rate than their normal cell compartment did, which contributed to the accumulation of the MDSCs in tumor-bearing hosts. Upregulation of glycolysis prevented excess reactive oxygen species (ROS) production by MDSCs, which protected MDSCs from apoptosis. Most importantly, we identified the glycolytic metabolite, phosphoenolpyruvate (PEP), as a vital antioxidant agent able to prevent excess ROS production and therefore contributed to the survival of MDSCs. These findings suggest that glycolytic metabolites have important roles in the modulation of fitness of MDSCs and could be potential targets for anti-MDSC strategy. Targeting MDSCs with analogs of specific glycolytic metabolites, for example, 2-phosphoglycerate or PEP may diminish the accumulation of MDSCs and reverse the immunosuppressive milieu in tumor-bearing individuals.

These findings indicated that shRNA could suppress HBV expression and replication for genotypes A, B, and C, promising an advance in treatment of HBV. However, the emergence of resistant mutants in HBV quasispecies should be considered.

We recently developed a mouse model of hepatitis B virus (HBV) persistence, in which a single i.v. hydrodynamic injection of HBV DNA to C57BL/6 mice allows HBV replication and induces a partial immune response, so that about 20-30% of the mice carry HBV for more than 6 months. The model was used to identify the viral antigen crucial for HBV persistence. We knocked out individual HBV genes by introducing a premature termination codon to the HBV core, HBeAg, HBx, and polymerase ORFs. The specific-genedeficient HBV mutants were hydrodynamically injected into mice and the HBV profiles of the mice were monitored. About 90% of the mice that received the HBcAg-mutated HBV plasmid exhibited high levels of hepatitis B surface antigenemia and maintained HBsAg expression for more than 6 months after injection. To map the region of HBcAg essential for viral clearance, we constructed a set of serial HBcAg deletion mutants for hydrodynamic injection. We localized the essential region of HBcAg to the carboxyl terminus, specifically to the 10 terminal amino acids (HBcAg176-185). The majority of mice receiving this HBV mutant DNA did not elicit a proper HBcAg-specific IFN-γ response and expressed HBV virions for 6 months. These results indicate that the immune response triggered in mice by HBcAg during exposure to HBV is important in determining HBV persistence.hepatitis B surface antigenemia | hydrodynamic injection P ersistent hepatitis B virus (HBV) infections affect about 350 million people worldwide and are a major health problem. Factors directing the infection toward chronicity have been studied extensively. The exposure of neonates or young children to a high HBV viral load, together with hepatitis B e antigen (HBeAg), predicts a high rate of persistent HBV infection. A recent genomewide association study identified HLA-DP polymorphisms as another factor in the persistence of HBV infections (1). Nevertheless, the immune mechanisms that lead to HBV persistence have not been resolved. To address this issue, a commonly used mouse model, such as the HBV transgenic mouse, has been used to study the possible mechanisms. However, the main drawback of HBV transgenic mouse models is that they are immunologically tolerant of viral antigens. Therefore, to explore the issue of HBV persistence, the adoptive transfer of HBV-primed immune cells or other manipulations must be used to overcome this tolerance. Another alternative is to introduce the HBV genome into the mouse liver by hydrodynamic injection through the tail vein. With this approach, HBV was shown to replicate in the mouse liver, and the immune responses against HBV proteins to clear the HBV infection could be documented in 1-2 weeks after the injection (2). Recently, we improved this approach by modifying the HBV DNA plasmid and injecting the plasmid into C57BL/6 mice and succeeded in delaying the mouse immune clearance of HBV (3). Clearance could be postponed for 6-8 weeks and about 10-30% of the injected mice maintained HBV persistence even up to 6 months after injection...

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The continuous torrential rain associated with a typhoon often caused flood, landslide or debris flow, leading to serious damages to Taiwan. Thus, a usable scheme to forecast rainfall amount during a typhoon period is highly desired. An analysis using hourly rainfall amounts taken at 371 stations during 1989-2001 showed that the topographical lifting of typhoon circulation played an important role in producing heavier rainfall. A climatology model for typhoon rainfall, which considered the topographical lifting and the variations of rain rate with radius was then developed. The model could provide hourly rainfall at any station or any river basin for a given typhoon center. The cumulative rainfall along the forecasted typhoon track was also available. The results showed that the R 2 value between the model estimated and the observed cumulative rainfall during the typhoon period for the DanShui (DSH) and Kao-Ping (KPS) River Basins reached 0.70 and 0.81, respectively. The R 2 values decreased slightly to 0.69 and 0.73 if individual stations were considered. However, the values decreased significantly to 0.40 and 0.51 for 3-hourly rainfalls, indicating the strong influence of the transient features in producing the heavier rainfall. In addition, the climatology model can only provide the average conditions. The characteristics in individual typhoons should be considered when applying the model in real-time operation. For example, the model could give reasonable cumulative rainfall amount at DSH before Nakri (2002) made landfall on Taiwan, but overestimated the rainfall after Nakri made landfall and weakened with significant reduction in convection.