Antiviral research最新文献

{"title":"Immunostimulatory effects of multiple short-hairpin RNAs enhance foot-and-mouth disease vaccine-induced humoral immunity","authors":"Aro Kim,&nbsp;Ji-Hyeon Hwang,&nbsp;Gyeongmin Lee,&nbsp;Jong-Hyeon Park,&nbsp;Min Ja Lee,&nbsp;Su-Mi Kim","doi":"10.1016/j.antiviral.2025.106202","DOIUrl":"10.1016/j.antiviral.2025.106202","url":null,"abstract":"<div><div>Small interfering RNAs are typically used to block gene expression via the sequence-specific degradation of mRNA. We previously developed a recombinant adenovirus expressing three short hairpin RNAs, targeting foot-and-mouth disease virus (FMDV) driven by the U6 promoter (Ad-3siRNA). These exhibited rapid antiviral effects against FMDV. Herein, we investigated the immunostimulatory effects of Ad-3siRNA in combination with an FMD inactivated vaccine. Ad-3siRNA induced various cytokines, including type I interferon, and upregulated interferon-stimulated genes in swine cells. Using the combination of Ad-3siRNA and a foot-and-mouth disease (FMD) inactivated vaccine, we observed enhanced protection efficacy until 1 week post-vaccination and enhanced neutralizing antibody levels from 1 week post-vaccination in mice. Furthermore, humoral immunity was significantly enhanced in pigs injected with a vaccine and a combination of Ad-3siRNA for 7 weeks post-vaccination. Ad-3siRNA induced various cytokines, such as IFN-α, IFN-γ, IL-12, IL-6, IL-15 and IL-18, in mice. In conclusion, we demonstrated that Ad-3siRNA, a novel immunostimulatory RNA delivered by a human adenoviral vector, could enhance protection and humoral immunity in combination with an FMD-inactivated vaccine. Exploring the applications of Ad-3siRNAs against other viral diseases and further detailed mechanistic studies are warranted.</div></div>","PeriodicalId":8259,"journal":{"name":"Antiviral research","volume":"240 ","pages":"Article 106202"},"PeriodicalIF":4.5,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144180748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term effects of peginterferon-based therapy versus nucleos(t)ide analogue monotherapy in non-cirrhotic HBeAg-positive chronic hepatitis B patients","authors":"Qiankun Hu ,&nbsp;Xueyun Zhang ,&nbsp;Xiongyue Cao ,&nbsp;Shuai Tao ,&nbsp;Chong Chen ,&nbsp;Mengxin Lu ,&nbsp;Conglin Zhao ,&nbsp;Liang Chen ,&nbsp;Qiang Li ,&nbsp;Xun Qi ,&nbsp;Yuxian Huang","doi":"10.1016/j.antiviral.2025.106192","DOIUrl":"10.1016/j.antiviral.2025.106192","url":null,"abstract":"<div><h3>Background &amp; aims</h3><div>The long-term clinical benefits of interferon (IFN)-based therapy compared to nucleos(t)ide analogue (NA) monotherapy in HBeAg-positive chronic hepatitis B (CHB) have not been well defined. This study aimed to evaluate the cumulative incidence of new-onset cirrhosis, serological responses, and hepatocellular carcinoma (HCC) development between these treatment strategies.</div></div><div><h3>Methods</h3><div>Two independent cohorts of non-cirrhotic, HBeAg-positive CHB patients were analyzed: a treatment-naïve cohort (n = 686) and an NA-experienced cohort (n = 531). Patients received either IFN-based therapy or NA monotherapy. Propensity score matching (PSM) was employed to minimize intergroup heterogeneity. The primary endpoint was the cumulative incidence of new-onset cirrhosis.</div></div><div><h3>Results</h3><div>After PSM, the 10-year cumulative incidence of new-onset cirrhosis was significantly lower in the IFN-based therapy group compared to the NA monotherapy group in both the treatment-naïve (3.3 % vs 20.0 %, <em>p</em> = 0.005) and NA-experienced (4.9 % vs 20.9 %, <em>p</em> = 0.034) cohorts. IFN-based therapy also resulted in significantly higher serological response rates across both cohorts, including HBeAg loss (treatment-naïve: 84.7 % vs 55.6 %; NA-experienced: 60.4 % vs 43.6 %, both <em>p</em> &lt; 0.001) and HBsAg loss (treatment-naïve: 14.3 % vs 5.7 %, <em>p</em> = 0.006; NA-experienced: 10.2 % vs 1.3 %, <em>p</em> &lt; 0.001). Subgroup analysis showed that patients receiving IFN-based therapy who achieved HBeAg loss within 96 weeks had the greatest long-term benefits, with lower cirrhosis incidence and higher HBsAg loss rates. Although the incidence of HCC was lower in the IFN-based group, the difference did not reach statistical significance (both <em>p</em> &gt; 0.05).</div></div><div><h3>Conclusions</h3><div>IFN-based therapy provides superior long-term benefits over NA monotherapy in reducing cirrhosis risk and enhancing serological responses in HBeAg-positive CHB patients.</div></div>","PeriodicalId":8259,"journal":{"name":"Antiviral research","volume":"240 ","pages":"Article 106192"},"PeriodicalIF":4.5,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144126440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Therapeutic determinants of melatonin in hepatitis caused by coxsackievirus B3 infection","authors":"Sheng-Yu You ,&nbsp;Li-Chiu Wang ,&nbsp;Huey-Pin Tsai ,&nbsp;Yin-Ping Teresa Teng ,&nbsp;Shun-Hua Chen ,&nbsp;Shih-Min Wang","doi":"10.1016/j.antiviral.2025.106191","DOIUrl":"10.1016/j.antiviral.2025.106191","url":null,"abstract":"<div><div>Coxsackievirus B (CVB) is the most recognized enteroviruses associated with acute hepatitis in neonates. It may develop into life-threatening fulminant hepatitis and disseminated intravascular coagulation. Melatonin is a potential agent against infection by modulating inflammation, apoptosis, and oxidative stress. The effect of melatonin on CVB3 replications, cytokine and chemokine productions, and liver damage in CVB3-infected Huh-7 and HepG2 cells were determined. A CVB3-infected hepatitis mouse model was used to explore antiviral, anti-inflammatory, anti-apoptotic, and immunomodulatory responses of melatonin treatment. Melatonin administration reduced viral proteins and viral titers in CVB3-infected cell lines. The expressions of Nrf2 and MST1 were increased, and the levels of cleaved caspase-9 and interleukin (IL)-1β were decreased after melatonin treatment. Melatonin decreased the mortality rate and clinical scores and improved liver damage markers in CVB3-infected mice. Melatonin treatment significantly decreased the viral loads in the liver, spleen, brain, and brain stem of CVB3-infected mice. In the liver of CVB3-infected mice, the expression of Nrf2 and MST1 was increased. Melatonin increased the levels of interferon (IFN)-γ and decreased the levels of IL-1β, IL-6, TNF-α, IL-10, RANTES, and MCP-1 in the serum of CVB3-infected mice. The monocyte expressions were increased after the melatonin treatment of CVB3-infected mice initially. The expressions of the T cells, NK cells, and dendritic cells were attenuated after melatonin treatment through course. Melatonin highlighted the antiviral, anti-inflammatory, anti-oxidative and immune regulatory responses against CVB3-infected hepatitis <em>in vitro</em> and <em>in vivo</em>. The clinical potential efficacy of melatonin treatment in CVB3-infected hepatitis is positive and convinced.</div></div>","PeriodicalId":8259,"journal":{"name":"Antiviral research","volume":"239 ","pages":"Article 106191"},"PeriodicalIF":4.5,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mode of antiviral action of the galactose-specific lectin, AJLec, on the Junin virus propagation","authors":"Shuzo Urata ,&nbsp;Meion Lee ,&nbsp;Tomoko Tsuruta ,&nbsp;Reo Igarashi ,&nbsp;Kohsuke Takeda ,&nbsp;Hideaki Unno","doi":"10.1016/j.antiviral.2025.106189","DOIUrl":"10.1016/j.antiviral.2025.106189","url":null,"abstract":"<div><div>Junin virus (JUNV), a member of <em>Arenaviridae</em>, is the causative agent of Argentine hemorrhagic fever (AHF). Available AHF treatments are limited; therefore, development of effective and safe treatments is required. Thus, in this study, novel lectins were examined for anti-JUNV activity. To evaluate JUNV propagation, a recombinant Junin virus vaccine strain (r3Candid #1/ZsGreen) containing the ZsGreen gene as a marker in the viral genome was used. The anti-JUNV effects of four types of marine organism-derived lectins collected in Japan, including the Nagasaki Prefecture, were examined. AJLec, which was extracted from the Sea Anemone <em>Anthopleura japonica</em>, reduced the number of infected cells and viral production. Infection and infection-surrogate assays revealed that incubation of AJLec with viruses and cells before infection, and maintaining it during infection, was required to exhibit full antiviral activity. Moreover, the anti-JUNV activity of AJLec was suppressed by the addition of lactose; hence, the anti-JUNV activity of AJLec was a result of its galactose recognition. This indicates the importance of galactose on the surface of the Junin virion and the cell membrane for entry into cells. Overall, these results provide new insights into the anti-JUNV activity of AJLec. Particularly, the potential of lectins as new antiviral agents that inhibit pathogenic arenavirus replication and propagation is promising.</div></div>","PeriodicalId":8259,"journal":{"name":"Antiviral research","volume":"240 ","pages":"Article 106189"},"PeriodicalIF":4.5,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144092722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural characterization of HIV fusion inhibitor LP-98: Insights into antiviral and resistance mechanisms","authors":"Nian Liu ,&nbsp;Yuanmei Zhu ,&nbsp;Huihui Chong ,&nbsp;Sheng Cui ,&nbsp;Yuxian He","doi":"10.1016/j.antiviral.2025.106190","DOIUrl":"10.1016/j.antiviral.2025.106190","url":null,"abstract":"<div><div>LP-98 is a lipopeptide-based HIV fusion inhibitor with exceptional potency and long-acting antiviral activity, currently in phase II clinical trials. In this study, we elucidated the structural basis of LP-98's antiviral activity and resistance mechanisms. Using AlphaFold3, we first predicted the six-helical bundle (6-HB) structure formed by LP-98 and the gp41-derived NHR peptide N44, identifying key residues mediating interhelical interactions. Subsequent crystallographic analysis of the LP-98/N44 complex confirmed these binding features, revealing that a cluster of hydrophobic residues in LP-98, along with a network of 15 hydrogen bonds, two electrostatic interactions and a salt bridge, critically stabilizes the 6-HB structure. Superposition analyses of the LP-98/N44 crystal structure with either the predicted 6-HB model or the LP-40/N44 crystal structure provided further mechanistic insights into LP-98's binding mode. Additionally, structural and functional characterization of the N-terminal Tyr-127 residue using a truncated variant (LP-98-Y) demonstrated its essential role in inhibitor binding and antiviral activity. Notably, LP-98 exhibited significantly reduced efficacy against T20-resistant HIV strains harboring single or double mutations in NHR. Our structural models shed light on the molecular basis of this resistance, offering critical insights for drug optimization. Collectively, these findings provide a detailed structural understanding of LP-98's antiviral mechanism, supporting its continued development as a promising next-generation HIV fusion inhibitor.</div></div>","PeriodicalId":8259,"journal":{"name":"Antiviral research","volume":"239 ","pages":"Article 106190"},"PeriodicalIF":4.5,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144089075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combinations of approved oral nucleoside analogues confer potent suppression of alphaviruses in vitro and in vivo","authors":"Sam Verwimp ,&nbsp;Jessica Wagoner ,&nbsp;Elijah Gabriela Arenas ,&nbsp;Lander De Coninck ,&nbsp;Rana Abdelnabi ,&nbsp;Jennifer L. Hyde ,&nbsp;Joshua T. Schiffer ,&nbsp;Judith M. White ,&nbsp;Jelle Matthijnssens ,&nbsp;Johan Neyts ,&nbsp;Stephen J. Polyak ,&nbsp;Leen Delang","doi":"10.1016/j.antiviral.2025.106186","DOIUrl":"10.1016/j.antiviral.2025.106186","url":null,"abstract":"<div><div>Alphaviruses, including chikungunya virus (CHIKV), pose a significant global health threat, yet specific antiviral therapies remain unavailable. We evaluated combinations of three oral directly acting antiviral drugs (sofosbuvir (SOF), molnupiravir (MPV), and favipiravir (FAV)), which are approved for other indications, against CHIKV, Semliki Forest virus (SFV), Sindbis virus (SINV), and Venezuelan Equine Encephalitis virus (VEEV) <em>in vitro</em> and <em>in vivo</em>. We assessed antiviral efficacy in human skin fibroblasts and liver cells, as well as in a mouse model of CHIKV-induced arthritis. In human skin fibroblasts, synergistic antiviral effects were observed for combinations of MPV + SOF and FAV + SOF against CHIKV, and for FAV + SOF against SFV. In human liver cells, FAV + MPV conferred additive to synergistic activity against VEEV and SINV, while SOF synergized with FAV against SINV. In mice, MPV improved CHIKV-induced foot swelling and reduced systemic infectious virus titres. Combination treatment with MPV and SOF significantly reduced swelling and infectious titres compared to monotherapies of each drug. Sequencing of CHIKV RNA from joint tissue revealed that MPV caused dose-dependent increases in mutations in the CHIKV genome. Upon combination therapy of MPV with SOF, the number of mutations was significantly lower compared to monotherapy with several higher doses of MPV. Combining these approved oral nucleoside analogues confers potent suppression of multiple alphaviruses <em>in vitro</em> and <em>in vivo</em> with enhanced control of viral genetic evolution in face of antiviral pressure. These drug combinations may ultimately lead to the development of potent combinations of pan-family alphavirus inhibitors.</div></div>","PeriodicalId":8259,"journal":{"name":"Antiviral research","volume":"239 ","pages":"Article 106186"},"PeriodicalIF":4.5,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144072362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pharmacokinetic and safety evaluation of lipopeptide-based HIV fusion inhibitor Lipovirtide in rats","authors":"Yuanmei Zhu ,&nbsp;Huihui Chong ,&nbsp;Nian Liu,&nbsp;Yuxian He","doi":"10.1016/j.antiviral.2025.106187","DOIUrl":"10.1016/j.antiviral.2025.106187","url":null,"abstract":"<div><div>Lipovirtide, originally designated as LP-80, is a stearic acid-modified lipopeptide HIV fusion inhibitor with highly potent and long-lasting anti-HIV activity, and it has already progressed to phase II clinical trials. In this report, we investigated the pharmacokinetics and safety profile of LP-80 in Sprague Dawley (SD) rats. LP-80 was absorbed rapidly following subcutaneous injection, exhibiting high absolute bioavailability (F): 92.32 % in male and 84.74 % in female. The time to reach maximum plasma concentration (T_max) ranged from 5.5 to 8 hours (h), and the elimination half-life (T_1/2) was between 6.26 and 7.47 h, indicating a relatively long-lasting presence in the bloodstream. LP-80 was widely distributed across various tissues, with the highest concentration observed in serum, suggesting effective systemic delivery and potential for targeting HIV in different compartments. Only a minimal amount of the parent drug was excreted in feces and urine, which indicates that LP-80 is metabolically stable and not rapidly cleared from the body. Acute, subchronic, and chronic toxicity studies demonstrated that LP-80 was well tolerated in animals, with no significant adverse effects observed. No anti-drug antibodies (ADA) were detected, suggesting low immunogenicity. Furthermore, LP-80 showed no toxic effects on fertility, embryo-fetal development, or offspring development. Collectively, our studies demonstrate that LP-80 is metabolically stable and exhibits a favorable safety profile, supporting its advancement into clinical trials for HIV treatment.</div></div>","PeriodicalId":8259,"journal":{"name":"Antiviral research","volume":"239 ","pages":"Article 106187"},"PeriodicalIF":4.5,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143949060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing human liver spheroids as a model for antiviral drug evaluation against BSL-3 haemorrhagic fever viruses","authors":"Sarah Chaput ,&nbsp;Jean-Sélim Driouich ,&nbsp;Simon Gruber ,&nbsp;Donna Busler ,&nbsp;Xavier de Lamballerie ,&nbsp;Antoine Nougairède ,&nbsp;Franck Touret","doi":"10.1016/j.antiviral.2025.106188","DOIUrl":"10.1016/j.antiviral.2025.106188","url":null,"abstract":"<div><div>Haemorrhagic fever viruses (HFVs) cause highly lethal syndromes with limited therapeutic options. Increasingly, 3D cell culture models are becoming an important tool in the field of virology. Since the liver is an important target for many HFVs, we evaluated a ready-to-use 96-well liver spheroid model composed of human primary cells for antiviral assessment. We worked with four biosafety level 3 (BSL-3) HFVs in this study: two orthoflaviviruses, Alkhumra haemorrhagic fever virus (AHFV) and yellow fever virus (YFV), and two viruses belonging to <em>Hareavirales</em> order, Pirital virus (PIRV), a surrogate for new-world BSL-4 mammarenaviruses, and Rift Valley fever virus (RVFV). We found that RVFV and PIRV were able to replicate in this model, whereas the orthoflaviviruses were not. A high viral dose was required for robust replication, and infectivity of RVFV in spheroids was low. We successfully demonstrated the antiviral activity of known broad-spectrum antiviral compounds—favipiravir, nitazoxanide, ribavirin, and galidesivir—despite some variability. However, except for ribavirin, higher doses were required in spheroids to detect antiviral effect compared to the 2D cell culture model. Overall, we conclude that human liver spheroids cannot replace traditional models for the selection of antiviral compounds but provide valuable additional complementary information. More broadly, this model could be useful to study viral pathogenicity and host-pathogen interactions.</div></div>","PeriodicalId":8259,"journal":{"name":"Antiviral research","volume":"239 ","pages":"Article 106188"},"PeriodicalIF":4.5,"publicationDate":"2025-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143952570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploiting host kinases to combat dengue virus infection and disease","authors":"Natasha M. Bourgeois ,&nbsp;Ling Wei ,&nbsp;Alexis Kaushansky ,&nbsp;John D. Aitchison","doi":"10.1016/j.antiviral.2025.106172","DOIUrl":"10.1016/j.antiviral.2025.106172","url":null,"abstract":"<div><div>The burden of dengue on human health has dramatically increased in recent years, underscoring the urgent need for effective therapeutic interventions. Despite decades of research since the discovery of the dengue virus, no specific antiviral treatments are available and strategies to reliably prevent severe disease remain limited. Direct-acting antivirals against dengue are under active investigation but have shown limited efficacy to date. An underappreciated Achille's heal of the virus is its dependence on host factors for infection and pathogenesis, each of which presents a potential avenue for therapeutic intervention. We and others have demonstrated that dengue virus relies on multiple host kinases, some of which are already targeted by clinically approved inhibitors. These offer drug repurposing opportunities for host-directed dengue treatment. Here, we summarize findings on the role of kinases in dengue infection and disease and highlight potential kinase targets for the development of innovative host-directed therapeutics.</div></div>","PeriodicalId":8259,"journal":{"name":"Antiviral research","volume":"241 ","pages":"Article 106172"},"PeriodicalIF":4.5,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143955099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of the polymerase acidic protein E199K substitution in influenza A viruses on baloxavir susceptibility","authors":"Emi Takashita ,&nbsp;Yoshihiro Yasui ,&nbsp;Asaka Ikegaya ,&nbsp;Kyohei Saka ,&nbsp;Noriyuki Maeshiro ,&nbsp;Hiroko Morita ,&nbsp;Shiho Nagata ,&nbsp;Seiichiro Fujisaki ,&nbsp;Hideka Miura ,&nbsp;Noriko Kishida ,&nbsp;Kazuya Nakamura ,&nbsp;Masayuki Shirakura ,&nbsp;Shinji Watanabe ,&nbsp;Hideki Hasegawa","doi":"10.1016/j.antiviral.2025.106173","DOIUrl":"10.1016/j.antiviral.2025.106173","url":null,"abstract":"<div><div>Baloxavir marboxil, a cap-dependent endonuclease inhibitor, was approved in Japan in 2018 for the treatment and prophylaxis of influenza. Its active form, baloxavir acid, binds to the polymerase acidic (PA) protein endonuclease domain, inhibiting viral RNA cleavage. PA substitutions (e.g., E23K, I38T, E199G) have been associated with reduced susceptibility to baloxavir. During nationwide monitoring in Japan, we identified influenza A(H1N1)pdm09 and A(H3N2) viruses carrying a PA E199K substitution. Database analysis revealed that PA E199K is rare, detected in only 0.01 % of A(H1N1)pdm09 and A(H3N2) viruses. Because its impact on baloxavir susceptibility has not been reported, here, we characterized PA E199K mutant viruses in vitro. Phenotypic analysis showed a 5.0–5.2-fold increase in baloxavir EC₅₀ values in PA E199K mutants, indicating reduced baloxavir susceptibility similar to PA E199G. However, replication efficiency of PA E199K mutants was significantly lower than wild-type viruses, suggesting impaired viral fitness. Unlike PA E199G, PA E199K introduces charge and steric changes that may further reduce replication capacity. While PA E199G mutants have led to a community cluster, PA E199K has only been detected sporadically, likely due to its greater impairment of viral replication. The PA E199K mutants were susceptible to neuraminidase inhibitors. Given the increasing global use of baloxavir, continuous monitoring of resistance-associated substitutions is essential for public health and clinical management.</div></div>","PeriodicalId":8259,"journal":{"name":"Antiviral research","volume":"239 ","pages":"Article 106173"},"PeriodicalIF":4.5,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143928714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}