Virology Journal最新文献

Rubus species, including raspberry and blackberry, are affected by over 40 known viruses that can impact fruit yield, plant vigor, and germplasm movement. These species differ markedly in their response to viral infection, yet the factors that contribute to susceptibility are unknown. We hypothesize this is due to differences in virus accumulation dynamics. We utilized an infectious clone of blackberry chlorotic ringspot virus to assess replication efficiency in 'Munger' black raspberry (Rubus occidentalis, L.), a virus indicator for Rubus viruses, and 'Natchez' blackberry (Rubus L. subgenus Rubus Watson), a cultivar that typically is asymptomatic to single virus infections. This study demonstrated that virus accumulation in 'Munger' is over 4.4 × 10⁵-fold higher than in 'Natchez,' based on a model-derived estimate averaged across sampling time points, providing evidence that the host genotype plays a key role in supporting virus replication. These findings deepen our understanding of virus-host interactions and further validate the use of 'Munger' as a virus indicator for Rubus.

Rotaviruses A (RVA) are the most common cause of diarrhea-related death in children under the age of five. Because RV vaccines are live attenuated, their use is limited. This work aimed to develop a multi-epitope vaccination against RVA using reverse vaccinology approaches. The viral protein 6 (VP6) was targeted for predicting B-cell and T-cell epitopes, and the best epitopes from its conserved regions were linked by appropriate linkers; additionally, 50 S ribosomal protein L7/L12 was inserted as an adjuvant to the vaccine's N-terminus. The designed vaccine revealed satisfactory antigenicity, allergenicity, toxicity, and physicochemical characteristics. The molecular docking and molecular dynamics (MD) simulation showed strong binding interactions between the vaccine and toll-like receptor 4 (TLR4), signifying improved antigen presentation efficacy. The vaccine immunity simulation showed a significant rise in immunoglobulins and cytokines. Furthermore, the vaccine candidate showed a high likelihood of successful expression in Escherichia coli (E. coli). Our findings suggest that the multi-epitope vaccine candidate exhibits significant potential; however, experimental evaluations are necessary to determine its ability to stimulate the immune system.

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) continues to pose significant public health in clinical settings due to its remarkable genomic plasticity and resistance to available therapeutic drugs, including carbapenems. Bacteriophage has emerged as an optimistic solution capable of addressing such drug resistance dilemma. This study represents a comprehensive characterization of a novel Acinetobacter phage with potential application against CRAB-associated wound infections.

Methods: Sewage sample was obtained, processed, and enriched with A. baumannii M13 phage(s) for the purpose of phages' isolation. The isolated phage was examined using transmission electron microscope (TEM) and identified in terms of host range and efficiency of plating through spot test and plaque assay, respectively. Phage stability was screened following thermal, pH and ethanol assays. Replication kinetics were investigated through adsorption and single step growth curve. Furthermore, the in-vitro antibacterial potential was verified through measuring the optical density of the treated M13 culture at different Multiplicity of infections (MOIs) over 6 h shaking incubation. This is in tandem with preliminary screening of the vB_AbaM_MU1 safety through genomic and phylogenetic analysis of the isolated phage.

Results: A novel lytic Acinetobacter phage vB_AbaM_MU1 was isolated and categorized as T4-like Myovirus with genomic size 167.200 bp, which was classified into the family Straboviridae in class Caudoviricetes, based on morphological and genomic analyses. It showed lytic efficiency against 9/17 CRAB strains. Infectivity and structural integrity revealed thermal stability up to 60℃, pH tolerance within pH range (3-11), sensitivity to different EtOH concentrations (10%, 50%, 75%, and 95%). In addition, vB_AbaM_MU1 displayed distinctive infection kinetics with 6 min adsorption, short latent (over 30 min), and high bursting (326 PFU/infected cell). The in-vitro bacteriolytic infectivity revealed robust and steady antibacterial action at MOI of 1 and above.

Conclusion: These findings provide a strong, well-justified foundation for considering vB_AbaM_MU1 phage as successful candidate for phage therapy in treating CRAB- induced wound infections.

Background: Hendra virus (HeV) is a bat-adapted zoonotic henipavirus belonging to the Paramyxoviridae family. It is classified as a biosafety level 4 (BSL-4) pathogen owing to its broad host range and high fatality rate. Currently, no vaccines or therapeutics are approved for human use. Viral entry is mediated by the attachment (G) and fusion (F) glycoproteins; the heavily glycosylated G protein is responsible for receptor binding.

Methods: The extracellular domain of HeV-G was expressed in Expi293F cells and its glycosylation sites and glycan composition were identified by mass spectrometry. A series of functional assays-including viral entry, receptor binding, cell-cell membrane fusion, antibody neutralization and immunogenicity-were performed to delineate the role of each N-linked glycosylation site.

Results: Glycan profiling of HeV-G identified seven N-linked and multiple O-linked glycosylation sites, revealing that the stalk residues (N72, N159) predominantly carry high-mannose glycans, whereas the head-domain N-glycan sites (N306, N378, N417, N481, N529) are primarily modified with complex glycans. Notably, among the head-domain sites, N481 also harbors a substantial proportion of high-mannose glycans. Functional assays revealed that removal of N-glycans at N159, N306 and N417 markedly reduced membrane fusion. The N159 residue is a key site for fusion triggering, and its function is tolerant to specific amino acid substitutions, which may contribute to stabilizing or facilitating the conformational cascade required for F protein-mediated membrane fusion. The N529Q mutant specifically decreased EB3 binding by 2.6-fold, correlating with reduced infectivity. Binding assays with neutralizing antibodies showed that most N-glycan deletions had negligible effects, except that N159Q and N481Q reduced affinity to nAH1.3. Immunization studies in mice demonstrated that N-glycans had minimal impact on humoral immunity, with only minor site-specific differences.

Conclusion: These findings provide a comprehensive characterization of HeV-G glycosylation, reveal site-specific roles of N-glycans in viral entry, receptor binding and membrane fusion, and offer new insights for vaccine and antibody development.

Background: Dengue fever continues to exert significant global impact, affecting populations worldwide with considerable public health and economic consequences. There is no antiviral drug for dengue. This study focuses on hypericin, a naturally occurring compound from Hypericum perforatum L. whose anti-dengue properties have been underexplored. We systematically examined its antiviral efficacy against dengue virus (DENV), revealing strong inhibitory effects and clarifying its precise antiviral mechanism.

Methods: The study assessed the efficacy of hypericin against DENV using various scientific methods like plaque assays and Western blotting. We looked into its antiviral mechanism. We used a time-of-addition approach during our research. Moreover, the basic mechanisms involved were studied through molecular docking, surface plasmon resonance (SPR), and co-immunoprecipitation (Co-IP).

Results: This study demonstrated that hypericin exhibits broad-spectrum antiviral activity against DENV-2 in cell lines derived from multiple species. In time-of-addition experiments, it showed inhibitory effects under co-treatment, direct virucidal, and post-treatment conditions. Crucially, hypericin primarily blocked viral attachment and entry stages, thereby effectively reducing intracellular viral load. Mechanistic investigations revealed a interaction between hypericin and the E protein, evidenced by a computational docking score of -7.0 kcal/mol and an experimental SPR-derived Kd of 7.18 µM. Furthermore, Co-IP assays demonstrated that hypericin competitively blocks the association between the E protein and its cellular receptor, HSP70.

Conclusion: As per these findings, the E protein was seen to be a target of hypericin with an antiviral activity against DENV-2 at multiple stages by limiting viral adsorption and viral entry projecting a molecular basis for the candidate molecule as a possible anti-dengue agent.

Phage therapy is currently gaining attention as a promising alternative for treating multi-drug resistant (MDR) bacterial infections, including urinary tract infections (UTIs). However, most studies have reported bacterial regrowth in vitro after hours of co-incubation with phage-host bacteria. In this study, we evaluated whether using a phage alone or combined with gentamicin could delay or prevent bacterial regrowth in vitro, in human urine, and in a rat model. The previously characterized lytic phage vB_Eco_ZCEC08 was combined with gentamicin to target clinical Uropathogenic Escherichia coli (UPEC) infection. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of gentamicin against the resistant EC08 clinical isolate were determined, revealing high gentamicin resistance (MIC = MBC, 500 µg/mL). Time-killing assays demonstrated that combining ½ MIC gentamicin (250 µg/mL) with the phage at different multiplicities of infection (MOIs) effectively controlled bacterial growth and prevented regrowth, even after 72 h, in both in vitro culture media and urine. Notably, the phage's growth exhibited distinct dynamics when used alone versus in combination with gentamicin in both in vitro and in vivo experiments. The combination showed higher replication rates in both urine and the rate model. For the in vivo experiments, bacterial counts showed significant reductions with both phage therapy and combination therapy compared to gentamicin monotherapy. Histopathological analysis of the tissues treated with the combination presented better tissue integrity than either monotherapy. These findings support the potential of phage-antibiotic combinations as an effective strategy against MDR-UPEC infections, highlighting the need for further studies to optimize treatment regimens for clinical applications.

Background: Chronic hepatitis B (CHB) with positive HBeAg status constitutes a significant contributor to the development of liver cirrhosis and hepatocellular carcinoma. Pegylated interferon-alpha (pegIFNα) is a common treatment, but its response rate remains limited, and the underlying mechanisms are not fully understood.

Methods: Eighty-two HBeAg-positive CHB patients were enrolled. miR-194-5p expression, HBeAg, and HBV DNA levels were detected using qRT-PCR, ELISA, and quantitative PCR, respectively. ROC and logistic regression analyses were performed. Cellular experiments, including dual-luciferase reporter and rescue assays, along with Western blot analysis of JAK-STAT pathway proteins, were conducted to verify targeting and function.

Results: Complete response (CR) patients had significantly lower baseline HBV DNA than suboptimal response (SR) patients. After 48 weeks of pegIFNα therapy, miR-194-5p expression decreased notably in the CR group and correlated positively with HBV DNA and HBeAg levels. miR-194-5p predicted treatment response with an AUC of 0.831 and was an independent predictor. Mechanistically, miR-194-5p targeted SOCS2. Functional studies demonstrated that miR-194-5p overexpression enhanced, while SOCS2 supplementation attenuated, pegIFNα-induced phosphorylation of STAT1/STAT2, thereby influencing cell viability and inflammatory factor expression (TNF-α, IL-6, IL-1β).

Conclusion: miR-194-5p may predict pegIFNα response in HBeAg-positive CHB. It regulates interferon signaling by targeting SOCS2 and modulating the JAK-STAT pathway activation, suggesting the miR-194-5p/SOCS2 axis as a potential therapeutic target.

Influenza A virus remains a persistent threat, continuously evolving and contributing to seasonal epidemics and potential pandemics. In this study, we analyzed clinical samples collected from pediatric patients in Shanghai between 2022 and 2023, following the SARS-CoV-2 pandemic, to assess the genetic diversity of circulating influenza A virus strains. Out of 88 clinical samples that were positive for influenza A virus, seven isolates were successfully cultured and subjected to whole-genome sequencing. Whole-genome sequencing was performed using the Illumina high-throughput sequencing platform, while missing genomic segments, which were identified in the whole-genome sequence of isolates, were later amplified via standard PCR and Sanger sequencing. Phylogenetic analysis revealed a significant divergence between H3N2 strains from 2023 to those from 2022, suggesting a potential decline in vaccine efficacy over successive seasons. A H1N1 strain isolated from 2022 exhibited close genetic similarity to the vaccine strain. Mutational analysis identified key substitutions in the hemagglutinin and neuraminidase regions, including the I222V mutation in the neuraminidase segment of sample B623080303, which is associated with strong resistance to oseltamivir and peramivir. Another highly drug-resistant N206D mutation in the hemagglutinin region, detected in four clinical isolates, was found to alter host specificity by reducing binding affinity to human-like α2,6-linked receptors while increasing affinity for avian-like α2,3-linked receptors, thereby influencing host adaptation dynamics. The findings provide critical insights into the evolutionary trends of influenza A virus strains post-COVID-19 pandemic and their potential implications for vaccine effectiveness and antiviral resistance.

Backgrounds &aims: Nucleos(t)ide analog (NAs) treatment achieves limited HBsAg loss rates; switching to or adding Peginterferon (PegIFN) therapy may improve outcomes. This study aimed to evaluate the efficacy of adding PegIFNα-2b therapy in chronic hepatitis B (CHB) patients who are virally suppressed by NAs.

Method: 250 CHB patients on NAs treatment with HBsAg < 1500 IU/mL, serum HBV DNA < 20 IU/mL, and ALT ≤ 1.5 × ULN were enrolled. Patients continued their NAs regimen and initiated PegIFNα-2b (180 µg/week) for 48 weeks, with follow-up until week 72. In addition to routine biochemistry, HBsAg and HBV RNA levels were measured at each visit; HBcrAg was assessed at baseline, week 12, and week 24.

Results: 214 patients completed 48 weeks of PegIFNα-2b therapy, and 34.6% achieved HBsAg loss at week 72. Lower baseline HBsAg was associated with higher rates of HBsAg clearance. Specifically, patients with baseline HBsAg < 10 IU/mL and 10-100 IU/mL achieved HBsAg clearance rates of 76.2% and 45.5% at week 72, respectively. In univariate analysis, baseline HBsAg and its decline at week 12 demonstrated the strongest predictive performance for HBsAg loss, while younger age and higher ALT were also associated with HBsAg clearance. However, in multivariate analysis, only age and HBsAg decline at week 12 remained independent predictors of HBsAg loss.

Conclusions: CHB patients with low HBsAg levels and virologic suppression on NAs can achieve significant HBsAg loss after adding PegIFNα-2b. A two-step strategy based on baseline HBsAg and week-12 HBsAg decline may aid patient selection and treatment optimization.

Background: West Nile virus (WNV) is primarily transmitted by the bite of Culex mosquitoes, but other mechanisms, such as blood transfusion, have also been described. Since its identification in the Americas in 1999, WNV has circulated consistently in the United States of America (USA); however, although WNV has been detected in humans in South America, no major outbreaks have occurred in more than 20 years. One of the hypotheses to explain this difference is the underdiagnosis of the infection. In Mexico, nine isolated cases have been officially reported since 2003 despite its proximity to the USA. In this study, we aim to demonstrate the circulation of WNV in blood donors from a northern border city of Mexico.

Methods: Between August and September of 2023, 86 serum samples from volunteer blood donors were collected to determine anti-WNV Immunoglobulin (Ig) G using a commercial enzyme-linked immunosorbent assay (ELISA) kit. In a subgroup of 44 samples, anti-WNV IgM was determined. To corroborate the IgM results, nucleic acid amplification tests (NAAT) were performed to determine RNA of WNV, Dengue and Zika. The participants were questioned about the history of travel to the USA; all of them were residents of the city of Nogales, Sonora, located on the border with the state of Arizona. For the comparison of seronegative and seropositive donor groups, the Chi-square test and Mann-Whitney U test were used for qualitative and quantitative variables, respectively. Additionally, a spatial analysis of seropositive cases was conducted.

Results: One sample was reactive to anti-WNV IgM and IgG; however, all NAAT results were negative. In addition, 19 samples were reactive for IgG, and no statistically significant differences were found between the groups. Seropositive cases showed a geographic pattern of clustering on the outskirts of the city, in areas with low population density.

Conclusions: Our results strongly suggest recent WNV circulation among residents from the northern border of Mexico. The lack of differences regarding the history and frequency of travel to the USA suggests that contact with the virus occurs in Mexico and that the low reported circulation in the region represents an underdiagnosis of the disease.