The influenza A virus (IAV), renowned for its high contagiousness and potential to catalyze global pandemics, poses significant challenges due to the emergence of drug-resistant strains. Given the critical role of RNA polymerase in IAV replication, it stands out as a promising target for anti-IAV therapies. In this study, we identified a novel C-3-substituted oleanolic acid benzyl amide derivative, A5, as a potent inhibitor of the PA_C-PB1_N polymerase subunit interaction, with an IC₅₀ value of 0.96 ± 0.21 μmol/L. A5 specifically targets the highly conserved PA_C domain and demonstrates remarkable efficacy against both laboratory-adapted and clinically isolated IAV strains, including multidrug-resistant strains, with EC₅₀ values ranging from 0.60 to 1.83 μmol/L. Notably, when combined with oseltamivir, A5 exhibits synergistic effects both in vitro and in vivo. In a murine model, dose-dependent administration of A5 leads to a significant reduction in IAV titers, resulting in a high survival rate among treated mice. Additionally, A5 treatment inhibits virus-induced Toll-like receptor 4 activation, attenuates cytokine responses, and protects against IAV-induced inflammatory responses in macrophages. In summary, A5 emerges as a novel inhibitor with high efficiency and broad-spectrum anti-influenza activity.

ObjectiveThe natural history of chronic HBV infection often involves a histologically defined immune tolerance state， and once such immune tolerance state is broken， antiviral therapy should be initiated immediately. This study aims to investigate the correlation between immune-mediated liver injury and virological indicators for HBV and precisely identify the patients with a histologically defined immune tolerance state. MethodsThis study was conducted among 577 HBeAg-positive chronic hepatitis B （CHB） patients with HBV DNA >2×10⁶ IU/mL who did not receive antiviral therapy in The Fifth Medical Center of PLA General Hospital， Tianjin Second People’s Hospital， Shanghai Ruijin Hospital， and Taizhou Hospital of Zhejiang Province from January 2010 to December 2022. Liver biopsy was performed to determine the extent of liver injury， and the serum levels of alanine aminotransferase （ALT）， aspartate aminotransferase （AST）， and virological indicators were measured. The proportion of patients with a histologically defined immune tolerance state was analyzed based on the cut-off values of noninvasive indicators recommended in various guidelines， especially HBV load. In addition， a diagnostic model was established for the histologically defined immune tolerance state based on serum HBV DNA at the time when its correlation with liver immunopathological injury disappeared as the new threshold in combination with multiple indicators. The Mann-Whitney U test was used for comparison of continuous data between two groups， and the chi-square test was used for comparison of categorical data between two groups. The Spearman method was used for correlation analysis. The binary Logistic regression analysis was used to establish a multivariate diagnostic model； the area under the receiver operating characteristic curve （AUC） was used to investigate the diagnostic efficiency of different models， and the Z test was used for comparison of AUC. ResultsAmong the patients with an immune tolerance state defined by the noninvasive indicators in the Chinese guidelines （2022 edition）， the EASL guidelines （2017 edition）， the AASLD guidelines （2018 edition）， and the APASL guidelines （2015 edition） for the prevention and treatment of CHB， the patients with a histologically defined immune tolerance state who met the definition in this article （HBV DNA>2×10⁶ IU/mL） accounted for 47.0%， 38.5%， 36.0%， and 44.6%， respectively， which did not exceed 50%. When the threshold of serum HBV DNA increased to >2×10⁸ IU/mL， although the correlation between immune-mediated liver injury and HBV DNA disappeared （r=-0.029， P=0.704）， the patients with a histologically defined immune tolerance state reached only 52.0%. In the cohort of 251 HBeAg-positive patients with serum HBV DNA >1×10⁸ IU/mL， there were significant differences in the levels of HBsAg， HBeAg， HBV DNA， ALT， and AST between the significant liver injury group with 140 children and the non-significant liver injury group with 111 patients （all P<0.05）， and the multivariate binary Logistic regression analysis showed that AST， HBV DNA， and HBeAg were influencing factors for histologically defined immune tolerance state in patients （all P<0.05）. Based on the above indicators and related clinical data， a predictive model was established as logit（P）=1.424－0.028×AST， with an AUC of 0.730， an optimal cut-off value of 30.5 U/L， a sensitivity of 52.8%， and a specificity of 84.1%. A total of 238 adult patients with chronic HBV infection who underwent liver biopsy in Taizhou Hospital of Zhejiang Province were enrolled as the validation cohort， and the analysis showed that the predictive model established in this study had a better efficiency than AST/ALT， FIB-4， and APRI， with an AUC of 0.698， 0.555， 0.518， and 0.373， respectively （all P<0.05）. ConclusionFor HBeAg-positive patients with chronic HBV infection and HBV DNA>2×10⁸ IU/mL， an AST level of >30.5 U/L might indicate the “breakdown” of histologically defined immune tolerance state.

Objective:To explore the relationship and dynamic changes between virological markers and hepatic pathological damage due to host anti-hepatitis B virus (HBV) immunity in the natural course of disease in chronic HBV infected patients.Methods:Two hundred and thirty-eight adult chronic HBV-infected patients who underwent liver biopsy from January 2016 to June 2022 in Taizhou Hospital, Zhejiang Province, were retrospectively selected. General clinical data such as age, gender, platelets, ALT, AST, albumin, HBV DNA, qHBsAg, HBeAg, and liver pathology diagnostic indexes such as the grade of liver necroinflammation and liver fibrotic stages of the patients were collected. The patients were grouped according to HBeAg status, and subgrouped according to different grades of liver necroinflammation and different HBV DNA loads. Statistical analyses were performed to compare the differences in HBV virologic marker levels between the groups, and the correlation between them and the indicators of hepatic inflammatory injury, such as ALT,AST, and the grade of liver necroinflammation in the patients.Results:The levels of HBV virological markers in HBeAg-positive patients with moderate or higher liver necroinflammatory grade (G≥2) were significantly lower than those with mild (no) liver necroinflammatory grade (G < 2) ( P < 0.01); whereas the opposite trend was observed in HBeAg-negative patients, with the levels of HBV DNA, and qHBsAg in the G≥2 subgroup being significantly higher than those in the G < 2 subgroup ( P < 0.01). Correspondingly, HBV DNA level and qHBsAg showed weak to moderately strong negative correlation with liver necroinflammatory grade and AST which was an indicator of hepatic inflammatory injury in HBeAg-positive patients ( P < 0.05); whereas in HBeAg-negative patients, they showed weak to moderately strong positive correlation with hepatic inflammatory activity and ALT, AST ( P < 0.001), in which qHBsAg showed only a weak positive correlation with patients' liver necroinflammatory grade ( P = 0.003). Further subgroup analyses of HBeAg-positive patients according to whether the HBV DNA level was > 2×10 6 IU/ml showed weak to moderate negative correlations between HBV virological markers and liver necroinflammatory grade as well as ALT and AST in the subgroup of patients with HBV DNA > 2×10 6 IU/ml ( P < 0.05); however, the negative correlation disappeared in patients who were still HBeAg positive and had HBV DNA ≤ 2×10 6 IU/ml. Moreover, HBV DNA and ALT, HBeAg and AST showed moderate positive correlation ( P < 0.05). Conclusion:We speculate that the activation of host anti-HBV immunity can efficiently inhibit HBV replication by targeting the infected hepatocytes, but only in the early phase of disease progression in HBeAg positive patients with HBV DNA high (> 2×10 6 IU/ml).