Junctional and somatic hypermutation-induced CX4C motif is critical for the recognition of a highly conserved epitope on HCV E2 by a human broadly neutralizing antibody.
连接和体细胞超突变诱导的 CX4C 基序对于人类广泛中和抗体识别 HCV E2 上高度保守的表位至关重要。
- 作者列表："Yi C","Xia J","He L","Ling Z","Wang X","Yan Y","Wang J","Zhao X","Fan W","Sun X","Zhang R","Ye S","Zhang R","Xu Y","Ma L","Zhang Y","Zhou H","Huang Z","Niu J","Long G","Lu J","Zhong J","Sun B
:Induction of broadly neutralizing monoclonal antibodies (bNAbs) that bind to the viral envelope glycoproteins is a major goal of hepatitis C virus (HCV) vaccine research. The study of bNAbs arising in natural infection is essential in this endeavor. We generated a human antibody, 8D6, recognizing the E2 protein of HCV isolated from a chronic hepatitis C patient. This antibody shows broadly neutralizing activity, which covers a pan-genotypic panel of cell culture-derived HCV virions (HCVcc). Functional and epitope analyses demonstrated that 8D6 can block the interaction between E2 and CD81 by targeting a highly conserved epitope on E2. We describe how the 8D6 lineage evolved via somatic hypermutation to achieve broad neutralization. We found that the V(D)J recombination-generated junctional and somatic hypermutation-induced disulfide bridge (C-C) motif in the CDRH3 is critical for the broad neutralization and binding activity of 8D6. This motif is conserved among a series of broadly neutralizing HCV antibodies, indicating a common binding model. Next, the 8D6 inferred germline (iGL) was reconstructed and tested for its binding affinity and neutralization activity. Interestingly, 8D6 iGL-mediated relatively strong inhibition of the 1b genotype PR79L9 strain, suggesting that PR79L9 may serve as a potential natural viral strain that provides E2 sequences that induce bNAbs. Overall, our detailed epitope mapping and genetic studies of the HCV E2-specific mAb 8D6 have allowed for further refinement of antigenic sites on E2 and reveal a new mechanism to generate a functional CDRH3, while its iGL can serve as a probe to identify potential HCV vaccine strains.
METHODS:BACKGROUND:Opioids are often prescribed for pain in cirrhosis and may increase the risk of hepatic encephalopathy (HE). AIMS:To assess the association between opioids and HE in patients with well-compensated cirrhosis. METHODS:We used the IQVIA PharMetrics (Durham, NC) database to identify patients aged 18-64 years with cirrhosis. We excluded patients with any decompensation event from 1 year before cirrhosis diagnosis to 6 months after cirrhosis diagnosis. Over the 6 months after cirrhosis diagnosis, we determined the duration of continuous opioid use and classified use into short term (1-89 days) and chronic (90-180 days). We assessed whether patients developed HE over the subsequent year (ie 6-18 months after cirrhosis diagnosis). We used a landmark analysis and performed multivariable Cox proportional hazards regression to assess associations between opioid use and HE, adjusting for relevant confounders. RESULTS:The cohort included 6451 patients with compensated cirrhosis, of whom 23.3% and 4.7% had short-term and chronic opioid prescriptions respectively. Over the subsequent year, HE occurred in 6.3% patients with chronic opioid prescriptions, 5.0% with short-term opioid prescriptions and 3.3% with no opioid prescriptions. In the multivariable model, an increased risk of HE was observed with short-term (adjusted hazard ratio, HR 1.44, 95% CI 1.07-1.94) and chronic opioid prescriptions (adjusted HR 1.83, 95% CI 1.07-3.12) compared to no opioid prescriptions. CONCLUSION:In this national cohort of privately insured patients with cirrhosis, opioid prescriptions were associated with the risk of incident HE. Opioid use should be minimised in those with cirrhosis and, when required, limited to short duration.
METHODS:BACKGROUND AND AIMS:Cirrhosis is characterized by extensive fibrosis of the liver and is a major cause of liver-related mortality. Cirrhosis is partially heritable but genetic contributions to cirrhosis have not been systemically explored. Here, we carry out association analyses with cirrhosis in two large biobanks and determine the effects of cirrhosis associated variants on multiple human disease/traits. METHODS:We carried out a genome-wide association analysis of cirrhosis as a diagnosis in UK BioBank (UKBB; 1088 cases vs. 407 873 controls) and then tested top-associating loci for replication with cirrhosis in a hospital-based cohort from the Michigan Genomics Initiative (MGI; 875 cases of cirrhosis vs. 30 346 controls). For replicating variants or variants previously associated with cirrhosis that also affected cirrhosis in UKBB or MGI, we determined single nucleotide polymorphism effects on all other diagnoses in UKBB (PheWAS), common metabolic traits/diseases and serum/plasma metabolites. RESULTS:Unbiased genome-wide association study identified variants in/near PNPLA3 and HFE, and candidate variant analysis identified variants in/near TM6SF2, MBOAT7, SERPINA1, HSD17B13, STAT4 and IFNL4 that reproducibly affected cirrhosis. Most affected liver enzyme concentrations and/or aspartate transaminase-to-platelet ratio index. PheWAS, metabolic trait and serum/plasma metabolite association analyses revealed effects of these variants on lipid, inflammatory and other processes including new effects on many human diseases and traits. CONCLUSIONS:We identified eight loci that reproducibly associate with population-based cirrhosis and define their diverse effects on human diseases and traits.
METHODS:BACKGROUND:Spontaneous bacterial peritonitis (SBP) is a serious complication in patients with liver cirrhosis. In recent years, it has been postulated that the rate of multidrug-resistant organisms (MDROs) is increasing, especially in nosocomial SBP patients. Aim of the present work was to investigate this hypothesis and its possible clinical consequences. MATERIALS AND METHODS:One hundred and three culture-positive patients between 2007 and 2014 were compared with 81 patients between 2015 and 2017, to study the change of microbiological profiles and their clinical consequences. The cirrhosis patients with bacterascites requiring treatment were included as well. RESULTS:The most prevalent Gram-negative bacteria isolated from ascites were Enterobacterales (31.6%) and in Gram-positive pathogens Staphylococci (22.8%). There was a significant increase in MDROs (22.3% ICU 40.7%, P = .048), accompanied by an increased incidence of sepsis (from 21.4% to 37.0%, P = .021), hepatorenal syndrome (from 40.8% to 58.0%, P = .007) and the need of catecholamine therapy (from 21.4% to 38.8%, P = .036). Nosocomial origin correlated with higher MDRO proportion, more complications and lower antimicrobial susceptibility rates in 12 commonly used antibiotics. MDROs were confirmed as an isolated predictor for inpatient mortality and complications in multivariable logistic regression. CONCLUSIONS:The feeling in clinical practice that MDROs have increased in the last 11 years could be confirmed in our study in Munich, Germany. Nosocomial SBP correlated with significantly higher MDRO rates (nearly 50%) and complication rates. In our opinion, an antibiotic combination with comprehensive effect should be taken into account in nosocomial SBP patients in this region.