Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-30 (of 39 Records) |
Query Trace: Mishin VP [original query] |
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Influenza C virus susceptibility to antivirals with different mechanisms of action
Chesnokov A , Ivashchenko AA , Matsuzaki Y , Takashita E , Mishin VP , Ivachtchenko AV , Gubareva LV . Antimicrob Agents Chemother 2024 e0172723 Antiviral susceptibility of influenza viruses was assessed using a high-content imaging-based neutralization test. Cap-dependent endonuclease inhibitors, baloxavir and AV5116, were superior to AV5115 against type A viruses, and AV5116 was most effective against PA mutants tested. However, these three inhibitors displayed comparable activity (EC(50) 8-22 nM) against type C viruses from six lineages. Banana lectin and a monoclonal antibody, YA3, targeting the hemagglutinin-esterase protein effectively neutralized some, but not all, type C viruses. |
New insights into the neuraminidase-mediated hemagglutination activity of influenza A(H3N2) viruses
Gao R , Pascua PNQ , Nguyen HT , Chesnokov A , Champion C , Mishin VP , Wentworth DE , Gubareva LV . Antiviral Res 2023 218 105719 Influenza virus neuraminidase (NA) can act as a receptor-binding protein, a role commonly attributed to hemagglutinin (HA). In influenza A(H3N2) viruses, three NA amino acid residues have previously been associated with NA-mediated hemagglutination: T148, D151, and more recently, H150. These residues are part of the 150-loop of the NA monomer. Substitutions at 148 and 151 arise from virus propagation in laboratory cell cultures, whereas changes at 150 occurred during virus evolution in the human host. In this study, we examined the effect of natural amino acid polymorphism at position 150 on NA-mediated hemagglutination. Using the A/Puerto Rico/8/34 backbone, we generated a comprehensive panel of recombinant A(H3N2) viruses that have different NAs but shared an HA that displays poor binding to red blood cells (RBCs). None of the tested substitutions at 150 (C, H, L, R, and S) promoted NA-binding. However, we identified two new determinants of NA-binding, Q136K and T439R, that emerged during virus culturing. Similar to T148I, both Q136K and T439R reduced NA enzyme activity by 48-86% and inhibition (14- to 173-fold) by the NA inhibitor zanamivir. NA-binding was observed when a virus preparation contained approximately 10% of NA variants with either T148I or T439R, highlighting the benefit of using deep sequencing in virus characterization. Taken together, our findings provide new insights into the molecular mechanisms underlying the ability of NA to function as a binding protein. Information gained may aid in the design of new and improved NA-targeting antivirals. |
Antiviral susceptibility of clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) viruses isolated from birds and mammals in the United States, 2022
Nguyen HT , Chesnokov A , De La Cruz J , Pascua PNQ , Mishin VP , Jang Y , Jones J , Di H , Ivashchenko AA , Killian ML , Torchetti MK , Lantz K , Wentworth DE , Davis CT , Ivachtchenko AV , Gubareva LV . Antiviral Res 2023 217 105679 Clade 2.3.4.4 b highly pathogenic avian influenza (HPAI) A (H5N1) viruses that are responsible for devastating outbreaks in birds and mammals pose a potential threat to public health. Here, we evaluated their susceptibility to influenza antivirals. Of 1015 sequences of HPAI A (H5N1) viruses collected in the United States during 2022, eight viruses (∼0.8%) had a molecular marker of drug resistance to an FDA-approved antiviral: three adamantane-resistant (M2-V27A), four oseltamivir-resistant (NA-H275Y), and one baloxavir-resistant (PA-I38T). Additionally, 31 viruses contained mutations that may reduce susceptibility to inhibitors of neuraminidase (NA) (n = 20) or cap-dependent endonuclease (CEN) (n = 11). A panel of 22 representative viruses was tested phenotypically. Overall, clade 2.3.4.4 b A (H5N1) viruses lacking recognized resistance mutations were susceptible to FDA-approved antivirals. Oseltamivir was least potent at inhibiting NA activity, while the investigational NA inhibitor AV5080 was most potent, including against NA mutants. A novel NA substitution T438N conferred 12-fold reduced inhibition by zanamivir, and in combination with the known marker N295S, synergistically affected susceptibility to all five NA inhibitors. In cell culture-based assays HINT and IRINA, the PA-I38T virus displayed 75- to 108-fold and 37- to 78-fold reduced susceptibility to CEN inhibitors baloxavir and investigational AV5116, respectively. Viruses with PA-I38M or PA-A37T showed 5- to 10-fold reduced susceptibilities. As HPAI A (H5N1) viruses continue to circulate and evolve, close monitoring of drug susceptibility is needed for risk assessment and to inform decisions regarding antiviral stockpiling. |
An optimized cell-based assay to assess influenza virus replication by measuring neuraminidase activity and its applications for virological surveillance
Patel MC , Flanigan D , Feng C , Chesnokov A , Nguyen HT , Elal AA , Steel J , Kondor RJ , Wentworth DE , Gubareva LV , Mishin VP . Antiviral Res 2022 208 105457 Year-round virological characterization of circulating epidemic influenza viruses is conducted worldwide to detect the emergence of viruses that may escape pre-existing immunity or acquire resistance to antivirals. High throughput phenotypic assays are needed to complement the sequence-based analysis of circulating viruses and improve pandemic preparedness. The recent entry of a polymerase inhibitor, baloxavir, into the global market further highlighted this need. Here, we optimized a cell-based assay that considerably streamlines antiviral and antigenic testing by replacing lengthy immunostaining and imaging procedures used in current assay with measuring the enzymatic activity of nascent neuraminidase (NA) molecules expressed on the surface of virus-infected cells. For convenience, this new assay was named IRINA (Influenza Replication Inhibition Neuraminidase-based Assay). IRINA was successfully validated to assess inhibitory activity of baloxavir on virus replication by testing a large set (>150) of influenza A and B viruses, including drug resistant strains and viruses collected during 2017-2022. To test its versatility, IRINA was utilized to evaluate neutralization activity of a broadly reactive human anti-HA monoclonal antibody, FI6, and post-infection ferret antisera, as well as the inhibition of NA enzyme activity by NA inhibitors. Performance of IRINA was tested in parallel using respective conventional assays. IRINA offers an attractive alternative to current phenotypic assays, while maintaining reproducibility and high throughput capacity. Additionally, the improved turnaround time may prove to be advantageous when conducting time sensitive studies, such as investigating a new virus outbreak. This assay can meet the needs of surveillance laboratories by providing a streamlined and cost-effective approach for virus characterization. |
Cluster of Oseltamivir-Resistant and Hemagglutinin Antigenically Drifted Influenza A(H1N1)pdm09 Viruses, Texas, USA, January 2020
Mohan T , Nguyen HT , Kniss K , Mishin VP , Merced-Morales AA , Laplante J , St George K , Blevins P , Chesnokov A , De La Cruz JA , Kondor R , Wentworth DE , Gubareva LV . Emerg Infect Dis 2021 27 (7) 1953-1957 Four cases of oseltamivir-resistant influenza A(H1N1)pdm09 virus infection were detected among inhabitants of a border detention center in Texas, USA. Hemagglutinin of these viruses belongs to 6B.1A5A-156K subclade, which may enable viral escape from preexisting immunity. Our finding highlights the necessity to monitor both drug resistance and antigenic drift of circulating viruses. |
Susceptibility of widely diverse influenza a viruses to PB2 polymerase inhibitor pimodivir.
Patel MC , Chesnokov A , Jones J , Mishin VP , De La Cruz JA , Nguyen HT , Zanders N , Wentworth DE , Davis TC , Gubareva LV . Antiviral Res 2021 188 105035 Pimodivir exerts an antiviral effect on the early stages of influenza A virus replication by inhibiting the cap-binding function of polymerase basic protein 2 (PB2). In this study, we used a combination of sequence analysis and phenotypic methods to evaluate pimodivir susceptibility of influenza A viruses collected from humans and other hosts. Screening PB2 sequences for substitutions previously associated with reduced pimodivir susceptibility revealed a very low frequency among seasonal viruses circulating in the U.S. during 2015-2020 (<0.01%; 3/11,934) and among non-seasonal viruses collected in various countries during the same period (0.2%; 18/8971). Pimodivir potently inhibited virus replication in two assays, a single-cycle HINT and a multi-cycle FRA, with IC(50) values in a nanomolar range. Median IC(50) values determined by HINT were similar for both subtypes of seasonal viruses, A (H1N1)pdm09 and A (H3N2), across three seasons. Human seasonal viruses with PB2 substitutions S324C, S324R, or N510K displayed a 27-317-fold reduced pimodivir susceptibility. In addition, pimodivir was effective at inhibiting replication of a diverse group of animal-origin viruses that have pandemic potential, including avian viruses of A (H5N6) and A (H7N9) subtypes. A rare PB2 substitution H357N was identified in an A (H4N2) subtype poultry virus that displayed >100-fold reduced pimodivir susceptibility. Our findings demonstrate a broad inhibitory activity of pimodivir and expand the existing knowledge of amino acid substitutions that can reduce susceptibility to this investigational antiviral. |
Detection of baloxavir resistant influenza A viruses using next generation sequencing and pyrosequencing methods.
Patel MC , Mishin VP , De La Cruz JA , Chesnokov A , Nguyen HT , Wilson MM , Barnes J , Kondor RJG , Wentworth DE , Gubareva LV . Antiviral Res 2020 182 104906 Baloxavir, a new antiviral drug targeting cap-dependent endonuclease activity of polymerase acidic (PA) protein of influenza viruses, is now approved in multiple countries. Several substitutions at isoleucine 38 in PA protein (e.g., PA-I38T) have been associated with decreased baloxavir susceptibility in vitro and in vivo. In recent years, next generation sequencing (NGS) analysis and pyrosequencing have been used by CDC and U.S. Public Health Laboratories to monitor drug susceptibility of influenza viruses. Here we described an improved pyrosequencing assay for detecting influenza A viruses carrying substitutions at PA-38. Cyclic and customized orders of nucleotide dispensation were evaluated, and pyrosequencing results were compared to those generated using NGS. Our data showed that the customized nucleotide dispensation has improved the pyrosequencing assay performance in identification of double mixtures (e.g., PA-38I/T); however, identification of PA-38 variants in triple mixtures remains a challenge. While NGS analysis indicated the presence of PA-I38K in one clinical specimen and isolate, our attempts to detect this mutation by pyrosequencing or recover the virus carrying PA-I38K in cell culture were unsuccessful, raising a possibility of a rarely occurring sequencing error. Overall, pyrosequencing provides a convenient means to detect baloxavir resistant influenza viruses when NGS is unavailable or a faster turnaround time is required. |
Susceptibility of influenza A, B, C, and D viruses to Baloxavir
Mishin VP , Patel MC , Chesnokov A , De La Cruz J , Nguyen HT , Lollis L , Hodges E , Jang Y , Barnes J , Uyeki T , Davis CT , Wentworth DE , Gubareva LV . Emerg Infect Dis 2019 25 (10) 1969-1972 Baloxavir showed broad-spectrum in vitro replication inhibition of 4 types of influenza viruses (90% effective concentration range 1.2-98.3 nmol/L); susceptibility pattern was influenza A > B > C > D. This drug also inhibited influenza A viruses of avian and swine origin, including viruses that have pandemic potential and those resistant to neuraminidase inhibitors. |
Replicative fitness of seasonal influenza A viruses with decreased susceptibility to baloxavir
Chesnokov A , Patel MC , Mishin VP , De La Cruz JA , Lollis L , Nguyen HT , Dugan V , Wentworth DE , Gubareva LV . J Infect Dis 2019 221 (3) 367-371 Susceptibility of influenza A viruses to baloxavir can be affected by changes at amino acid residue 38 in polymerase acidic (PA) protein. Information on replicative fitness of PA-I38-substituted viruses remains sparse. We demonstrated that substitutions I38L/M/S/T not only had a differential effect on baloxavir susceptibility (9- to 116-fold), but also on in vitro replicative fitness. While I38L conferred undiminished growth, other substitutions led to mild attenuation. In a ferret model, control viruses outcompeted those carrying I38M or I38T substitutions, although their advantage was limited. These findings offer insights into the attributes of baloxavir resistant viruses needed for informed risk assessment. |
Detection of oseltamivir-resistant zoonotic and animal influenza A viruses using the rapid influenza antiviral resistance test.
Hodges EN , Mishin VP , De la Cruz J , Guo Z , Nguyen HT , Fallows E , Stevens J , Wentworth DE , Davis CT , Gubareva LV . Influenza Other Respir Viruses 2019 13 (5) 522-7 Mutations in the influenza virus neuraminidase (NA) that cause reduced susceptibility to the NA inhibitor (NAI) oseltamivir may occur naturally or following antiviral treatment. Currently, detection uses either a traditional NA inhibition assay or gene sequencing to identify known markers associated with reduced inhibition by oseltamivir. Both methods are laborious and require trained personnel. The influenza antiviral resistance test (iART), a prototype system developed by Becton, Dickinson and Company for research use only, offers a rapid and simple method to identify such viruses. This study investigated application of iART to influenza A viruses isolated from non-human hosts with a variety of NA subtypes (N1-N9). |
Insights into the antigenic advancement of influenza A(H3N2) viruses, 2011-2018.
Jorquera PA , Mishin VP , Chesnokov A , Nguyen HT , Mann B , Garten R , Barnes J , Hodges E , De La Cruz J , Xu X , Katz J , Wentworth DE , Gubareva LV . Sci Rep 2019 9 (1) 2676 Influenza A(H3N2) viruses evade human immunity primarily by acquiring antigenic changes in the haemagglutinin (HA). HA receptor-binding features of contemporary A(H3N2) viruses hinder traditional antigenic characterization using haemagglutination inhibition and promote selection of HA mutants. Thus, alternative approaches are needed to reliably assess antigenic relatedness between circulating viruses and vaccines. We developed a high content imaging-based neutralization test (HINT) to reduce antigenic mischaracterization resulting from virus adaptation to cell culture. Ferret reference antisera were raised using clinical specimens containing viruses representing recent vaccine strains. Analysis of viruses circulating during 2011-2018 showed that gain of an N158-linked glycosylation in HA was a molecular determinant of antigenic distancing between A/Hong Kong/4801/2014-like (clade 3C.2a) and A/Texas/50/2012-like viruses (clade 3C.1), while multiple evolutionary HA F193S substitution were linked to antigenic distancing from A/Switzerland/97152963/2013-like (clade 3C.3a) and further antigenic distancing from A/Texas/50/2012-like viruses. Additionally, a few viruses carrying HA T135K and/or I192T showed reduced neutralization by A/Hong Kong/4801/2014-like antiserum. Notably, this technique elucidated the antigenic characteristics of clinical specimens, enabling direct characterization of viruses produced in vivo, and eliminating in vitro culture, which rapidly alters the genotype/phenotype. HINT is a valuable new antigenic analysis tool for vaccine strain selection. |
Assessing baloxavir susceptibility of influenza viruses circulating in the United States during the 2016/17 and 2017/18 seasons
Gubareva LV , Mishin VP , Patel MC , Chesnokov A , Nguyen HT , De La Cruz J , Spencer S , Campbell AP , Sinner M , Reid H , Garten R , Katz JM , Fry AM , Barnes J , Wentworth DE . Euro Surveill 2019 24 (3) The anti-influenza therapeutic baloxavir targets cap-dependent endonuclease activity of polymerase acidic (PA) protein. We monitored baloxavir susceptibility in the United States with next generation sequencing analysis supplemented by phenotypic one-cycle infection assay. Analysis of PA sequences of 6,891 influenza A and B viruses collected during 2016/17 and 2017/18 seasons showed amino acid substitutions: I38L (two A(H1N1)pdm09 viruses), E23G (two A(H1N1)pdm09 viruses) and I38M (one A(H3N2) virus); conferring 4-10-fold reduced susceptibility to baloxavir. |
Monitoring influenza virus susceptibility to oseltamivir using a new rapid assay, iART
Gubareva LV , Fallows E , Mishin VP , Hodges E , Brooks A , Barnes J , Fry AM , Kramp W , Shively R , Wentworth DE , Weidemaier K , Jacobson R . Euro Surveill 2017 22 (18) A new rapid assay for detecting oseltamivir resistance in influenza virus, iART, was used to test 149 clinical specimens. Results were obtained for 132, with iART indicating 41 as 'resistant'. For these, sequence analysis found known and suspected markers of oseltamivir resistance, while no such markers were detected for the remaining 91 samples. Viruses isolated from the 41 specimens showed reduced or highly reduced inhibition by neuraminidase inhibition assay. iART may facilitate broader antiviral resistance testing. |
Antiviral drug-resistant influenza B viruses carrying H134N substitution in neuraminidase, Laos, February 2016
Baranovich T , Vongphrachanh P , Ketmayoon P , Sisouk T , Chomlasack K , Khanthamaly V , Nguyen HT , Mishin VP , Marjuki H , Barnes JR , Garten RJ , Stevens J , Wentworth DE , Gubareva LV . Emerg Infect Dis 2017 23 (4) 686-690 In February 2016, three influenza B/Victoria/2/87 lineage viruses exhibiting 4- to 158-fold reduced inhibition by neuraminidase inhibitors were detected in Laos. These viruses had an H134N substitution in the neuraminidase and replicated efficiently in vitro and in ferrets. Current antiviral drugs may be ineffective in controlling infections caused by viruses harboring this mutation. |
A Pyrosequencing-Based Approach to High-Throughput Identification of Influenza A(H3N2) Virus Clades Harboring Antigenic Drift Variants.
Mishin VP , Baranovich T , Garten R , Chesnokov A , Abd Elal AI , Adamczyk M , LaPlante J , George KS , Fry AM , Barnes J , Chester SC , Xu X , Katz JM , Wentworth DE , Gubareva LV . J Clin Microbiol 2016 55 (1) 145-154 Rapid evolution of influenza A(H3N2) viruses necessitates close monitoring of their antigenic properties so emergence and spread of antigenic drift variants can be rapidly identified. Changes in hemagglutinin (HA) acquired by contemporary A(H3N2) viruses hinder antigenic characterization by traditional methods, thus complicating vaccine strain selection. Sequence-based approaches have been used to infer virus antigenicity; however, they are time-consuming and mid-throughput. To facilitate virological surveillance and epidemiological studies, we have developed and validated a pyrosequencing approach that enables identification of six HA clades of contemporary A(H3N2) viruses. The identification scheme of H3 clade 3C.2, 3C.2a, 3C.2b, 3C.3, 3C.3a and 3C.3b viruses is based on the interrogation of five SNPs within three neighboring HA regions: 412-431; 465-481; and 559-571. Two bioinformatics tools, IdentiFire (Qiagen) and FireComb (developed in-house) were utilized to expedite pyrosequencing data analysis. The assay's analytical sensitivity was 10 focus forming units; and respiratory specimens with CT value < 34 typically produced good quality pyrograms. When applied to 120 A(H3N2) virus isolates and 27 respiratory specimens, the assay displayed 100% agreement with clades determined by HA sequencing coupled with phylogenetics. The multi-SNP analysis described here was readily adopted by another laboratory with pyrosequencing capabilities. Implementation of this approach enhanced virological surveillance and epidemiological studies from 2013-2016 when over 3000 A(H3N2) viruses were examined. |
Human monoclonal antibody 81.39a effectively neutralizes emerging influenza A viruses of group 1 and 2 hemagglutinins
Marjuki H , Mishin VP , Chai N , Tan MW , Newton EM , Tegeris J , Erlandson K , Willis M , Jones J , Davis T , Stevens J , Gubareva LV . J Virol 2016 90 (23) 10446-10458 The pandemic threat posed by emerging zoonotic influenza A viruses necessitate development of antiviral agents effective against various antigenic subtypes. Human monoclonal antibody (hmAb) targeting the hemagglutinin (HA) stalk offers a promising approach to control influenza virus infections. Here we investigated the ability of hmAb 81.39a to inhibit in vitro replication of human and zoonotic viruses, representing 16 HA subtypes. The majority of viruses were effectively neutralized by 81.39a, EC50 <0.01-4.9mug/ml. Among group 2 HA viruses tested, a single A(H7N9) virus was not neutralized at 50mug/ml; it contained HA2-Asp19Gly, an amino acid position previously associated with resistance to neutralization by the group 2 HA-neutralizing mAb CR8020. Notably, among group 1 HA viruses, H11-H13, and H16 subtypes were not neutralized at 50mug/ml; they shared a substitution HA2-Asp19Asn/Ala. Conversely, H9 viruses harboring HA2-Asp19Ala were fully susceptible to neutralization. Therefore, amino acid variance at HA2-Asp19 has subtype-specific adverse effects on in vitro neutralization. Mice given a single injection (15 or 45 mg/kg) at 24 or 48 hours after infection with recently emerged A(H5N2), A(H5N8), A(H6N1) or A(H7N9) viruses were protected from mortality and showed drastically reduced lung viral titers. Furthermore, 81.39a protected mice infected with A(H7N9) harboring HA2-Asp19Gly, although the antiviral effect was lessened. A(H1N1)pdm09-infected ferrets receiving a single dose (25 mg/kg) had reduced viral titers and showed less lung tissue injury, despite 24-72 hours delayed treatment. Taken together, this study provides experimental evidence for the therapeutic potential of 81.39a against diverse influenza A viruses. IMPORTANCE: Zoonotic influenza viruses, such as A(H5N1) and A(H7N9) subtypes, have caused severe disease and deaths in humans raising public health concerns. Development of novel anti-influenza therapeutics with a broad spectrum of activity against various subtypes is necessary to mitigate disease severity. Here we demonstrate that the hemagglutinin (HA) stalk-targeting human monoclonal antibody 81.39a effectively neutralized the majority of influenza A viruses tested, representing 16 HA subtypes. Furthermore, 81.39a delayed treatment significantly suppressed virus replication in the lungs, prevented dramatic body weight loss and increased survival rates of mice infected with A(H5Nx), A(H6N1) or A(H7N9) viruses. When tested in ferrets, 81.39a delayed treatment reduced viral titers, particularly in the lower respiratory tract, and substantially alleviated disease symptoms associated with severe A(H1N1)pdm09 influenza. Collectively, our data demonstrated the effectiveness of 81.39a against both seasonal and emerging influenza A viruses. |
Enhanced genetic characterization of influenza A(H3N2) viruses and vaccine effectiveness by genetic group, 2014-2015.
Flannery B , Zimmerman RK , Gubareva LV , Garten RJ , Chung JR , Nowalk MP , Jackson ML , Jackson LA , Monto AS , Ohmit SE , Belongia EA , McLean HQ , Gaglani M , Piedra PA , Mishin VP , Chesnokov AP , Spencer S , Thaker SN , Barnes JR , Foust A , Sessions W , Xu X , Katz J , Fry AM . J Infect Dis 2016 214 (7) 1010-9 BACKGROUND: During the 2014-15 US influenza season, expanded genetic characterization of circulating influenza A(H3N2) viruses was used to assess the impact of genetic variability of influenza A(H3N2) viruses on influenza vaccine effectiveness (VE). METHODS: A novel pyrosequencing assay was used to determine genetic group based on hemagglutinin (HA) gene sequences of influenza A(H3N2) viruses from patients enrolled US Flu Vaccine Effectiveness network sites. Vaccine effectiveness was estimated using a test-negative design comparing vaccination among patients infected with influenza A(H3N2) viruses and uninfected patients. RESULTS: Among 9710 enrollees, 1868 (19%) tested positive for influenza A(H3N2); genetic characterization of 1397 viruses showed 1134 (81%) belonged to one HA genetic group (3C.2a) of antigenically drifted H3N2 viruses. Effectiveness of 2014-15 influenza vaccination varied by A(H3N2) genetic group from 1% (95% confidence interval [CI], -14% to 14%) against illness caused by antigenically drifted A(H3N2) group 3C.2a viruses versus 44% (95% CI, 16% to 63%) against illness caused by vaccine-like A(H3N2) group 3C.3b viruses. CONCLUSION: Effectiveness of 2014-15 influenza vaccination varied by genetic group of influenza A(H3N2) virus. Changes in hemagglutinin genes related to antigenic drift were associated with reduced vaccine effectiveness. |
The molecular characterizations of surface proteins hemagglutinin and neuraminidase from recent H5Nx avian influenza viruses.
Yang H , Carney PJ , Mishin VP , Guo Z , Chang JC , Wentworth DE , Gubareva LV , Stevens J . J Virol 2016 90 (12) 5770-5784 During 2014, a subclade 2.3.4.4 HPAI A(H5N8) virus caused poultry outbreaks around the world. In late 2014/early 2015 the virus was detected in wild birds in Canada and the U.S. and these viruses also gave rise to reassortant progeny, composed of viral RNA segments (vRNAs) from both Eurasian and North America lineages. In particular, viruses were found with N1, N2 and N8 neuraminidase vRNAs, and are collectively referred to as H5Nx viruses. In the U. S., more than 48 million domestic birds have been affected. Here, we present a detailed structural and biochemical analysis of the surface antigens from H5N1, H5N2 and H5N8 in addition to a recent human H5N6 virus. Our results with recombinant hemagglutinin reveal that these viruses have a strict avian receptor binding preference, while recombinantly expressed neuraminidases are sensitive to FDA approved and investigational antivirals. Although H5Nx viruses currently pose a low risk to humans, it is important to maintain surveillance of these circulating viruses, and to continually assess future changes that may increase their pandemic potential. IMPORTANCE: The H5Nx viruses emerging in North America, Europe, and Asia are of great public health concern. Herein, we report a molecular and structural study of the major surface proteins from several H5Nx influenza viruses. Our results improve the understanding of these new viruses and provide important information on their receptor preference and susceptibility to antivirals, which is central to pandemic risk assessment. |
Effectiveness of seasonal influenza vaccine in preventing influenza primary care visits and hospitalisation in Auckland, New Zealand in 2015: interim estimates
Bissielo A , Pierse N , Huang QS , Thompson MG , Kelly H , Mishin VP , Turner N . Euro Surveill 2015 21 (1) Preliminary results for influenza vaccine effectiveness (VE) against acute respiratory illness with circulating laboratory-confirmed influenza viruses in New Zealand from 27 April to 26 September 2015, using a case test-negative design were 36% (95% confidence interval (CI): 11-54) for general practice encounters and 50% (95% CI: 20-68) for hospitalisations. VE against hospitalised influenza A(H3N2) illnesses was moderate at 53% (95% CI: 6-76) but improved compared with previous seasons. |
Standardizing the influenza neuraminidase inhibition assay among United States public health laboratories conducting virological surveillance
Okomo-Adhiambo M , Mishin VP , Sleeman K , Saguar E , Guevara H , Reisdorf E , Griesser RH , Spackman KJ , Mendenhall M , Carlos MP , Healey B , St George K , Laplante J , Aden T , Chester S , Xu X , Gubareva LV . Antiviral Res 2016 128 28-35 BACKGROUND: Monitoring influenza virus susceptibility to neuraminidase (NA) inhibitors (NAIs) is vital for detecting drug-resistant variants, and is primarily assessed using NA inhibition (NI) assays, supplemented by NA sequence analysis. However, differences in NI testing methodologies between surveillance laboratories results in variability of 50% inhibitory concentration (IC50) values, which impacts data sharing, reporting and interpretation. In 2011, the Centers for Disease Control and Prevention (CDC), in collaboration with the Association for Public Health Laboratories (APHL) spearheaded efforts to standardize fluorescence-based NI assay testing in the United States (U.S.), with the goal of achieving consistency of IC50 data. METHODS: For the standardization process, three participating state public health laboratories (PHLs), designated as National Surveillance Reference Centers for Influenza (NSRC-Is), assessed the NAI susceptibility of the 2011-12 CDC reference virus panel using stepwise procedures with support from the CDC reference laboratory. Next, the NSRC-Is assessed the NAI susceptibility of season 2011-12 U.S. influenza surveillance isolates (n=940), with a large subset (n=742) tested in parallel by CDC. Subsequently, U.S. influenza surveillance isolates (n=9629) circulating during the next three influenza seasons (2012-15), were independently tested by the three NSRC-Is (n=7331) and CDC (n=2298). RESULTS: The NI assay IC50s generated by respective NSRC-Is using viruses and drugs prepared by CDC were similar to those obtained with viruses and drugs prepared in-house, and were uniform between laboratories. IC50s for U.S. surveillance isolates tested during four consecutive influenza seasons (2011-15) were consistent from season to season, within and between laboratories. CONCLUSION: These results show that the NI assay is robust enough to be standardized, marking the first time IC50 data have been normalized across multiple laboratories, and used for U.S. national NAI susceptibility surveillance. |
Emergence of multidrug resistant influenza A(H1N1)pdm09 virus variants in an immunocompromised child treated with oseltamivir and zanamivir
Tamura D , DeBiasi RL , Okomo-Adhiambo M , Mishin VP , Campbell AP , Loechelt B , Wiedermann BL , Fry AM , Gubareva LV . J Infect Dis 2015 212 (8) 1209-13 Prolonged treatment of an immunocompromised child with oseltamivir and zanamivir for A(H1N1)pdm09 virus infection led to the emergence of viruses carrying H275Y and/or E119G in the neuraminidase. When phenotypically evaluated by neuraminidase inhibition, the dual H275Y-E119G substitution caused highly reduced inhibition by four neuraminidase inhibitors including oseltamivir, zanamivir, peramivir and laninamivir. |
Neuraminidase mutations conferring resistance to oseltamivir in influenza A(H7N9) viruses
Marjuki H , Mishin VP , Chesnokov AP , De La Cruz JA , Davis CT , Villanueva JM , Fry AM , Gubareva LV . J Virol 2015 89 (10) 5419-26 Human infections by avian influenza A(H7N9) virus entail substantial morbidity and mortality. Treatment of infected patients with the neuraminidase (NA) inhibitor oseltamivir was associated with emergence of viruses carrying NA substitutions. In the NA inhibition (NI) assay, R292K conferred highly reduced inhibition by oseltamivir, while E119V and I222K each caused reduced inhibition. To facilitate establishment of laboratory correlates of clinically relevant resistance, experiments were conducted in ferrets infected with virus carrying wild-type or variant NA genes recovered from the A/Taiwan/1/2013 isolate. Oseltamivir treatment (5 or 25 mg/kg/dose) was given 4 hours post-infection followed by twice daily treatment for 5 days. Treatment of ferrets infected with wild-type virus resulted in a modest dose-dependent reduction (0.7-1.5 log10TCID50) in nasal wash viral titers and inflammation response. Conversely, treatment failed to significantly inhibit the replication of R292K or E119V viruses. A small reduction of viral titers was detected on day 5 in ferrets infected with the I222K virus. Propensity for oseltamivir resistance emergence was assessed in oseltamivir-treated animals infected with wild-type virus; emergence of R292K virus was detected in 3 of 6 ferrets within 5-7 days post-infection. Collectively, we demonstrate that R292K, E119V and I222K reduced the inhibitory activity of oseltamivir not only in the NI assay, but also in infected ferrets, judged particularly by viral loads in nasal washes, and may signal the need for alternative therapeutics. Thus, these clinical outcomes measured in the ferret model may correlate with clinically relevant oseltamivir resistance in humans. IMPORTANCE: This report provides more evidence for using the ferret model to assess susceptibility of influenza A(H7N9) viruses to oseltamivir, the most prescribed anti-influenza drug. The information gained can be used to assist in the establishment of laboratory correlates of human disease and drug therapy. The rapid emergence of viruses with R292K in treated ferrets correlates well with the multiple reports on this NA variant in treated human patients. Our findings highlight the importance for discovery and characterization of new antiviral drugs with different mechanism of action and the use of combination treatment strategies against emerging viruses with pandemic potential such as avian H7N9 virus, particularly against those carrying drug resistance markers. |
Application of a Seven-Target Pyrosequencing Assay To Improve the Detection of Neuraminidase Inhibitor-Resistant Influenza A(H3N2) Viruses.
Tamura D , Okomo-Adhiambo M , Mishin VP , Guo Z , Xu X , Villanueva J , Fry AM , Stevens J , Gubareva LV . Antimicrob Agents Chemother 2015 59 (4) 2374-9 National U.S. influenza antiviral surveillance incorporates data generated by neuraminidase (NA) inhibition (NI) testing of isolates supplemented with NA sequence analysis; and pyrosequencing analysis of clinical specimens. Lack of established correlates for clinically relevant resistance to NA inhibitors (NAIs) hinders interpretation of NI assay data. Nonetheless, A(H3N2) viruses are commonly monitored for highly reduced or reduced inhibition in the NI assay and/or presence of NA markers, E119V, R292K and N294S. In 2012-2013, three drug resistant A(H3N2) viruses were detected by NI assay among isolates (n=1424); all showed highly reduced inhibition by oseltamivir and had E119V. In addition, one R292K variant was detected among clinical samples (n=1024) by a 3-target pyrosequencing assay. Overall, frequency of NAI resistance was low, 0.16% (4 of 2448). To screen for additional NA markers previously identified in viruses from NAI-treated patients, the pyrosequencing assay was modified to include Q136K, I222V, del245-248 and del247-250. The 7-target pyrosequencing assay detected NA variants carrying E119V, Q136 and del245-248 in an isolate from an oseltamivir-treated patient. Next, this assay was applied to clinical specimens collected from hospitalized patients and submitted for NI testing, but failed cell culture propagation. Of the 27 clinical specimens tested, 4 (15%) contained NA changes: R292K (n=2), E119V (n=1) and del247-250 (n=1). Recombinant NAs with del247-250 and del245-248, respectively, conferred highly reduced inhibition by oseltamivir, reduced inhibition by zanamivir, and normal inhibition by peramivir and laninamivir. Our results demonstrated the benefits of the 7-target pyrosequencing assay in conducting A(H3N2) antiviral surveillance and testing for clinical care. |
Characterization of drug-resistant influenza A(H7N9) variant viruses isolated from an oseltamivir-treated patient in Taiwan
Marjuki H , Mishin VP , Chesnokov AP , Jones J , De La Cruz JA , Sleeman K , Tamura D , Nguyen HT , Wu HS , Chang FY , Liu MT , Fry AM , Cox NJ , Villanueva JM , Davis CT , Gubareva LV . J Infect Dis 2014 211 (2) 249-57 BACKGROUND: Patients contracting influenza A(H7N9) often developed severe disease causing respiratory failure. Neuraminidase (NA) inhibitors (NAIs) are the primary option for treatment, but information on drug-resistance markers for A(H7N9) is limited. METHODS: Four NA variants of A/Taiwan/1/2013 (H7N9) virus containing a single substitution (NA-E119 V, NA-I222 K, NA-I222R or NA-R292 K), recovered from an oseltamivir-treated patient, were tested for NAI susceptibility in vitro; their replicative fitness was evaluated in cell culture, mice and ferrets. RESULTS: NA-R292 K led to highly reduced inhibition by oseltamivir and peramivir, while NA-E119 V, NA-I222 K and NA-I222R caused reduced inhibition by oseltamivir. Mice infected with any virus showed severe clinical signs with high mortality rates. NA-I222 K virus was the most virulent in mice, whereas virus lacking NA change (NA-WT) and NA-R292 K virus seemed the least virulent. Sequence analysis suggests that PB2-S714N increased virulence of the NA-I222 K virus in mice; NS1-K126R, alone or in combination with PB2-V227M, produced contrasting effects in NA-WT and NA-R292 K viruses. In ferrets, all viruses replicated to high titers in the upper respiratory tract, but produced only mild illness. NA-R292 K virus, showed reduced replicative fitness in this animal model. CONCLUSIONS: Our data highlight challenges in assessment of replicative fitness of H7N9 NA variants emerged in NAI-treated patients. |
Antiviral susceptibility of variant influenza A(H3N2)v viruses isolated in the United States from 2011 to 2013
Sleeman K , Mishin VP , Guo Z , Garten RJ , Balish A , Fry AM , Villanueva J , Stevens J , Gubareva LV . Antimicrob Agents Chemother 2014 58 (4) 2045-51 Since 2011, outbreaks caused by influenza A(H3N2) variant [A(H3N2)v] viruses have become a public health concern in the United States. The A(H3N2)v viruses share the A(H1N1)pdm09 M gene containing the marker of M2 blocker resistance, S31N, but do not contain any known molecular markers associated with resistance to neuraminidase (NA) inhibitors (NAIs). Using a fluorescent NA inhibition (NI) assay, the susceptibilities of recovered A(H3N2)v viruses (n = 168) to FDA-approved (oseltamivir and zanamivir) and other (peramivir, laninamivir, and A-315675) NAIs were assessed. All A(H3N2)v viruses tested, with the exception of a single virus strain, A/Ohio/88/2012, isolated from an untreated patient, were susceptible to the NAIs tested. The A/Ohio/88/2012 virus contained two rare substitutions, S245N and S247P, in the NA and demonstrated reduced inhibition by oseltamivir (31-fold) and zanamivir (66-fold) in the NI assay. Using recombinant NA (recNA) proteins, S247P was shown to be responsible for the observed altered NAI susceptibility, in addition to an approximately 60% reduction in NA enzymatic activity. The S247P substitution has not been previously reported as a molecular marker of reduced susceptibility to the NAIs. Using cell culture assays, the investigational antiviral drugs nitazoxanide, favipiravir, and fludase were shown to inhibit the replication of A(H3N2)v viruses, including the virus with the S247P substitution in the NA. This report demonstrates the importance of continuous monitoring of susceptibility of zoonotic influenza viruses to available and investigational antiviral drugs. |
An investigational antiviral drug, DAS181, effectively inhibits replication of zoonotic influenza A virus subtype H7N9 and protects mice from lethality
Marjuki H , Mishin VP , Chesnokov AP , De La Cruz JA , Fry AM , Villanueva J , Gubareva LV . J Infect Dis 2014 210 (3) 435-40 Human infections caused by the avian influenza A(H7N9) virus have been associated with substantial morbidity and mortality. Emergence of virus variants, carrying markers of decreased susceptibility to neuraminidase inhibitors, was reported. Here we showed that fludase, an antiviral drug with sialidase activity, potently inhibited replication of wild-type H7N9 viruses and their oseltamivir-resistant R292 K variants in mice. A once-daily administration initiated early after lethal infection, hampered body weight loss and completely protected mice from lethality. We observed a time-dependent effect for 24-72-hour delayed fludase treatments on morbidity and mortality. The results warrant further investigation of fludase for influenza treatment. |
Antiviral susceptibility of highly pathogenic avian influenza A(H5N1) viruses isolated from poultry, Vietnam, 2009-2011
Nguyen HT , Nguyen T , Mishin VP , Sleeman K , Balish A , Jones J , Creanga A , Marjuki H , Uyeki TM , Nguyen DH , Nguyen DT , Do HT , Klimov AI , Davis CT , Gubareva LV . Emerg Infect Dis 2013 19 (12) 1963-71 We assessed drug susceptibilities of 125 avian influenza A(H5N1) viruses isolated from poultry in Vietnam during 2009-2011. Of 25 clade 1.1 viruses, all possessed a marker of resistance to M2 blockers amantadine and rimantadine; 24 were inhibited by neuraminidase inhibitors. One clade 1.1 virus contained the R430W neuraminidase gene and reduced inhibition by oseltamivir, zanamivir, and laninamivir 12-, 73-, and 29-fold, respectively. Three of 30 clade 2.3.4 viruses contained a I223T mutation and showed 7-fold reduced inhibition by oseltamivir. One of 70 clade 2.3.2.1 viruses had the H275Y marker of oseltamivir resistance and exhibited highly reduced inhibition by oseltamivir and peramivir; antiviral agents DAS181 and favipiravir inhibited H275Y mutant virus replication in MDCK-SIAT1 cells. Replicative fitness of the H275Y mutant virus was comparable to that of wildtype virus. These findings highlight the role of drug susceptibility monitoring of H5N1 subtype viruses circulating among birds to inform antiviral stockpiling decisions for pandemic preparedness. |
Cell culture-selected substitutions in influenza A(H3N2) neuraminidase affect drug susceptibility assessment
Tamura D , Nguyen HT , Sleeman K , Levine M , Mishin VP , Yang H , Guo Z , Okomo-Adhiambo M , Xu X , Stevens J , Gubareva LV . Antimicrob Agents Chemother 2013 57 (12) 6141-6 Assessment of drug susceptibility has become an integral part of influenza virus surveillance. In this study, we describe the drug resistance profile of influenza A(H3N2) virus, A/Mississippi/05/2011, collected from a patient treated with oseltamivir and detected via surveillance. An MDCK cell-grown isolate of this virus exhibited highly reduced inhibition by the neuraminidase (NA) inhibitors (NAIs) oseltamivir (8,005-fold), zanamivir (813-fold), peramivir (116-fold), and laninamivir (257-fold) in the NA inhibition assay. Sequence analysis of its NA gene revealed a known oseltamivir-resistance marker, the glutamic acid-to-valine substitution at position 119 (E119V), and an additional change, threonine to isoleucine at position 148 (T148I). Unlike E119V, T148I was not detected in the clinical sample but acquired during viral propagation in MDCK cells. Using recombinant proteins, T148I by itself was shown to cause only a 6-fold increase in the zanamivir 50% inhibitory concentration (IC50) and had no effect on inhibition by other drugs. The T148I substitution reduced NA activity by 50%, most likely by affecting the positioning of the 150 loop at the NA catalytic site. Using pyrosequencing, changes at T148 were detected in 35 (23%) of 150 MDCK cell-grown A(H3N2) viruses tested, which was lower than the frequency of changes at D151 (85%), an NA residue previously implicated in cell selection. We demonstrate that culturing of the A(H3N2) viruses (n = 11) at a low multiplicity of infection delayed the emergence of the NA variants with changes at position 148 and/or 151, especially when conducted in MDCK-SIAT1 cells. Our findings highlight the current challenges in monitoring susceptibility of influenza A(H3N2) viruses to the NAI class of antiviral drugs. |
The effect of the MDCK cell selected neuraminidase D151G mutation on the drug susceptibility assessment of influenza A(H3N2) viruses.
Mishin VP , Sleeman K , Levine M , Carney PJ , Stevens J , Gubareva LV . Antiviral Res 2013 101 93-6 Propagation of influenza A(H3N2) viruses in MDCK cells has been associated with the emergence of neuraminidase (NA) variants carrying a change at residue 151. In this study, the pyrosequencing assay revealed that approximately 90% of A(H3N2) virus isolates analyzed (n=150) contained more than one amino acid variant (D/G/N) at position 151. Susceptibilities of the virus isolates to zanamivir and oseltamivir were assessed using the chemiluminescent and fluorescent NA inhibition (NI) assays. In the chemiluminescent assay, which utilizes NA-Star(R) substrate, up to 13-fold increase in zanamivir-IC50 was detected for isolates containing a high proportion (>50%) of the G151 NA variant. However, an increase in zanamivir-IC50s was not seen in the fluorescent assay, which uses MUNANA as substrate. To investigate this discrepancy, recombinant NAs (rNAs) were prepared and tested in both NI assays. Regardless of the assay used, the zanamivir-IC50 for the rNA G151 was much greater (>1500-fold) than that for rNA D151 wild-type. However, zanamivir resistance conferred by the G151 substitution was masked in preparations containing the D151 NA which had much greater activity, especially against MUNANA. In conclusion, the presence of NA D151G variants in cell culture-grown viruses interferes with drug susceptibility assessment and therefore measures need to be implemented to prevent their emergence. |
Bioluminescence-based neuraminidase inhibition assay for monitoring influenza drug susceptibility in clinical specimens
Marjuki H , Mishin VP , Sleeman K , Okomo-Adhiambo M , Sheu TG , Guo L , Xu X , Gubareva LV . Antimicrob Agents Chemother 2013 57 (11) 5209-15 The QFlu prototype bioluminescence-based neuraminidase (NA) inhibition (NI) assay kit was designed to detect NA inhibitor (NAI)-resistant influenza viruses at point-of-care. Here we evaluated its suitability for drug susceptibility assessment at a surveillance laboratory. A comprehensive panel of reference viruses (n=14) and a set of 90 seasonal influenza A and B isolates were included for testing with oseltamivir and/or zanamivir in the QFlu assay using the manufacturer recommended protocol and a modified version to attune to surveillance requirement. The generated IC50s were compared with the NI assays currently used for monitoring influenza drug susceptibility, the fluorescent (FL) and chemiluminescent (CL) assays. To provide proof-of-principal, clinical specimens (n=235) confirmed by real-time RT-PCR to contain influenza A(H1N1)pdm09 virus and pre-screened for the oseltamivir resistance marker H275Y using pyrosequencing, were subsequently tested in the QFlu assay. All three NI assays were able to discriminate the reference NA variants and their matching wild-types based on the difference in their IC50s. Unless the antigenic types were first identified, certain NA variants (e.g. H3N2 with E119V) could only be detected among seasonal viruses using the FL assays. Notably, the QFlu assay identified oseltamivir-resistant A(H1N1)pdm09 viruses carrying the H275Y marker directly in clinical specimens, which is not feasible with the other two phenotypic assays that required prior virus culturing in cells. Furthermore, The QFlu assay allows detection of the influenza A and B virus isolates carrying established and potential NA inhibitor-resistance markers, and may become a useful tool for monitoring drug resistance in clinical specimens. |
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