scholarly journals Replication competent, 10-segmented influenza viruses as antiviral therapeutics

2019 ◽  
Author(s):  
Griffin D. Haas ◽  
Alfred T. Harding ◽  
Nicholas S. Heaton
Keyword(s):  
Influenza A ◽  
Viral Disease ◽  
Viral Assembly ◽  
Influenza Viruses ◽  
Wild Type Virus ◽  
Wild Type ◽  
Influenza A Viruses ◽  
Viral Spread ◽  
Naturally Occurring ◽  
Viral Particles

AbstractInfluenza A viruses (IAVs) encode their genome as eight negative sense RNA segments. During viral assembly, the failure to package all eight segments, or packaging of a mutated segment, renders the resultant virion incompletely infectious. It is known that the accumulation of these defective particles can limit viral disease by interfering with the spread of fully infectious particles. In order to harness this phenomenon therapeutically, we defined which viral packaging signals were amenable to duplication and developed a viral genetic platform which allowed the production of replication competent IAVs that package up to two additional artificial genome segments for a total of 10 segments. These artificial genome segments are capable of acting as “decoy” segments that, when packaged by wild-type (WT) viruses, lead to the production of non-infectious viral particles. Despite 10-segmented viruses being able to replicate and spreadin vivo, these genomic modifications render the viruses avirulent. Excitingly, administration of 10-segmented viruses, both prophylactically and therapeutically, was able to rescue animals from normally lethally influenza virus infections. Thus, 10-segmented influenza viruses represent a potent anti-influenza biological therapy that targets the strain-independent process of viral assembly to slow the kinetics of productive viral spread and therefore limit viral disease.Author SummarySeasonal influenza infections are best prevented using vaccination. Vaccination, however, is not capable of completely preventing influenza infection, necessitating the use of anti-influenza therapeutics. To date, several different classes of anti-influenza therapeutics have been developed and used in order to combat these infections. Unfortunately, the incidence of influenza resistance to many of these therapeutics has begun to rise, necessitating the development of new strategies. One such strategy is to mimic the activity of naturally occurring viral particles that harbor defective genomes. These defective interfering particles have the ability to interfere with productive viral assembly, preventing the spread of influenza viruses across the respiratory tract. Furthermore, given the manner in which they target influenza segment packaging, a conserved feature of all influenza A viruses, resistance to this therapeutic strategy is unlikely. Here, we report the development of a genetic platform that allows the production of replication competent, 10-segmented influenza viruses. These viruses are capable of amplifying themselves in isolation, but co-infection with a wild-type virus leads to segment exchange and compromises the spread of both viruses. This interference, while mechanistically distinct from naturally occurring defective particles, was able to target the same viral process and rescue animals exposed to an otherwise lethal viral infection. This viral-based approach may represent a cost effective and scalable method to generate effective anti-influenza therapeutics when vaccines or anti-viral drugs become ineffective due to acquisition of viral resistance mutations.

scholarly journals Attenuation and immunogenicity in mice of temperature-sensitive influenza viruses expressing truncated NS1 proteins

2005 ◽  
Vol 86 (10) ◽  
pp. 2817-2821 ◽  
Author(s):  
Ana M. Falcón ◽  
Ana Fernandez-Sesma ◽  
Yurie Nakaya ◽  
Thomas M. Moran ◽  
Juan Ortín ◽  
...  
Keyword(s):  
Influenza A ◽  
Influenza Viruses ◽  
Wild Type Virus ◽  
Temperature Sensitive ◽  
Ns1 Protein ◽  
Wild Type ◽  
Influenza A Viruses ◽  
Lethal Challenge

It was previously shown that two mutant influenza A viruses expressing C-terminally truncated forms of the NS1 protein (NS1-81 and NS1-110) were temperature sensitive in vitro. These viruses contain HA, NA and M genes derived from influenza A/WSN/33 H1N1 virus (mouse-adapted), and the remaining five genes from human influenza A/Victoria/3/75 virus. Mice intranasally infected with the NS1 mutant viruses showed undetectable levels of virus in lungs at day 3, whereas those infected with the NS1 wild-type control virus still had detectable levels of virus at this time. Nevertheless, the temperature-sensitive mutant viruses induced specific cellular and humoral immune responses similar to those induced by the wild-type virus. Mice immunized with the NS1 mutant viruses were protected against a lethal challenge with influenza A/WSN/33 virus. These results indicate that truncations in the NS1 protein resulting in temperature-sensitive phenotypes in vitro correlate with attenuation in vivo without compromising viral immunogenicity, an ideal characteristic for live attenuated viral vaccines.

scholarly journals The Cytoplasmic Tail of the Influenza A Virus M2 Protein Plays a Role in Viral Assembly

2006 ◽  
Vol 80 (11) ◽  
pp. 5233-5240 ◽  
Author(s):  
Kiyoko Iwatsuki-Horimoto ◽  
Taisuke Horimoto ◽  
Takeshi Noda ◽  
Maki Kiso ◽  
Junko Maeda ◽  
...  
Keyword(s):  
Amino Acids ◽  
Influenza A ◽  
Virus Assembly ◽  
Cytoplasmic Tail ◽  
Viral Assembly ◽  
Wild Type Virus ◽  
Type Virus ◽  
M2 Protein ◽  
Wild Type ◽  
Influenza A Viruses

ABSTRACT The viral replication cycle concludes with the assembly of viral components to form progeny virions. For influenza A viruses, the matrix M1 protein and two membrane integral glycoproteins, hemagglutinin and neuraminidase, function cooperatively in this process. Here, we asked whether another membrane protein, the M2 protein, plays a role in virus assembly. The M2 protein, comprising 97 amino acids, possesses the longest cytoplasmic tail (54 residues) of the three transmembrane proteins of influenza A viruses. We therefore generated a series of deletion mutants of the M2 cytoplasmic tail by reverse genetics. We found that mutants in which more than 22 amino acids were deleted from the carboxyl terminus of the M2 tail were viable but grew less efficiently than did the wild-type virus. An analysis of the virions suggested that viruses with M2 tail deletions of more than 22 carboxy-terminal residues apparently contained less viral ribonucleoprotein complex than did the wild-type virus. These M2 tail mutants also differ from the wild-type virus in their morphology: while the wild-type virus is spherical, some of the mutants were filamentous. Alanine-scanning experiments further indicated that amino acids at positions 74 to 79 of the M2 tail play a role in virion morphogenesis and affect viral infectivity. We conclude that the M2 cytoplasmic domain of influenza A viruses plays an important role in viral assembly and morphogenesis.

scholarly journals Broadly Reactive H2 Hemagglutinin Vaccines Elicit Cross-Reactive Antibodies in Ferrets Preimmune to Seasonal Influenza A Viruses

mSphere ◽  
2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Z. Beau Reneer ◽  
Amanda L. Skarlupka ◽  
Parker J. Jamieson ◽  
Ted M. Ross
Keyword(s):  
Influenza Virus ◽  
Immune Responses ◽  
Recombinant Proteins ◽  
Human Population ◽  
Influenza A ◽  
Seasonal Influenza ◽  
Influenza Viruses ◽  
Wild Type ◽  
Influenza A Viruses ◽  
Global Pandemic

ABSTRACT Influenza vaccines have traditionally been tested in naive mice and ferrets. However, humans are first exposed to influenza viruses within the first few years of their lives. Therefore, there is a pressing need to test influenza virus vaccines in animal models that have been previously exposed to influenza viruses before being vaccinated. In this study, previously described H2 computationally optimized broadly reactive antigen (COBRA) hemagglutinin (HA) vaccines (Z1 and Z5) were tested in influenza virus “preimmune” ferret models. Ferrets were infected with historical, seasonal influenza viruses to establish preimmunity. These preimmune ferrets were then vaccinated with either COBRA H2 HA recombinant proteins or wild-type H2 HA recombinant proteins in a prime-boost regimen. A set of naive preimmune or nonpreimmune ferrets were also vaccinated to control for the effects of the multiple different preimmunities. All of the ferrets were then challenged with a swine H2N3 influenza virus. Ferrets with preexisting immune responses influenced recombinant H2 HA-elicited antibodies following vaccination, as measured by hemagglutination inhibition (HAI) and classical neutralization assays. Having both H3N2 and H1N1 immunological memory regardless of the order of exposure significantly decreased viral nasal wash titers and completely protected all ferrets from both morbidity and mortality, including the mock-vaccinated ferrets in the group. While the vast majority of the preimmune ferrets were protected from both morbidity and mortality across all of the different preimmunities, the Z1 COBRA HA-vaccinated ferrets had significantly higher antibody titers and recognized the highest number of H2 influenza viruses in a classical neutralization assay compared to the other H2 HA vaccines. IMPORTANCE H1N1 and H3N2 influenza viruses have cocirculated in the human population since 1977. Nearly every human alive today has antibodies and memory B and T cells against these two subtypes of influenza viruses. H2N2 influenza viruses caused the 1957 global pandemic and people born after 1968 have never been exposed to H2 influenza viruses. It is quite likely that a future H2 influenza virus could transmit within the human population and start a new global pandemic, since the majority of people alive today are immunologically naive to viruses of this subtype. Therefore, an effective vaccine for H2 influenza viruses should be tested in an animal model with previous exposure to influenza viruses that have circulated in humans. Ferrets were infected with historical influenza A viruses to more accurately mimic the immune responses in people who have preexisting immune responses to seasonal influenza viruses. In this study, preimmune ferrets were vaccinated with wild-type (WT) and COBRA H2 recombinant HA proteins in order to examine the effects that preexisting immunity to seasonal human influenza viruses have on the elicitation of broadly cross-reactive antibodies from heterologous vaccination.

scholarly journals A Genetically Engineered Waterfowl Influenza Virus with a Deletion in the Stalk of the Neuraminidase Has Increased Virulence for Chickens

2009 ◽  
Vol 84 (2) ◽  
pp. 940-952 ◽  
Author(s):  
S. Munier ◽  
T. Larcher ◽  
F. Cormier-Aline ◽  
D. Soubieux ◽  
B. Su ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Cultured Cells ◽  
Genetically Engineered ◽  
Influenza Viruses ◽  
Wild Type Virus ◽  
Wild Type ◽  
Moderate Growth

ABSTRACT A deletion of about 20 amino acids in the stalk of the neuraminidase (NA) is frequently detected upon transmission of influenza A viruses from waterfowl to domestic poultry. Using reverse genetics, a recombinant virus derived from a wild duck influenza virus isolate, A/Mallard/Marquenterre/Z237/83 (MZ), and an NA stalk deletion variant (MZ-delNA) were produced. Compared to the wild type, the MZ-delNA virus showed a moderate growth advantage on avian cultured cells. In 4-week-old chickens inoculated intratracheally with the MZ-delNA virus, viral replication in the lungs, liver, and kidneys was enhanced and interstitial pneumonia lesions were more severe than with the wild-type virus. The MZ-delNA-inoculated chickens showed significantly increased levels of mRNAs encoding interleukin-6 (IL-6), transforming growth factor-β4 (TGF-β4), and CCL5 in the lungs and a higher frequency of apoptotic cells in the liver than did their MZ-inoculated counterparts. Molecular mechanisms possibly underlying the growth advantage of the MZ-delNA virus were explored. The measured enzymatic activities toward a small substrate were similar for the wild-type and deleted NA, but the MZ-delNA virus eluted from chicken erythrocytes at reduced rates. Pseudoviral particles expressing the MZ hemagglutinin in combination with the MZ-NA or MZ-delNA protein were produced from avian cultured cells with similar efficiencies, suggesting that the deletion in the NA stalk does not enhance the release of progeny virions and probably affects an earlier step of the viral cycle. Overall, our data indicate that a shortened NA stalk is a strong determinant of adaptation and virulence of waterfowl influenza viruses in chickens.

scholarly journals Human trials with wild-type H1N1 and recombinant H3N2-H1N1 influenza A viruses of 1977-1978

1980 ◽  
Vol 28 (3) ◽  
pp. 753-761
Author(s):  
A S Beare ◽  
A P Kendal ◽  
N J Cox ◽  
C Scholtissek
Keyword(s):  
Influenza A ◽  
H1n1 Influenza ◽  
Clinical Effects ◽  
Wild Type ◽  
Influenza A Viruses ◽  
Recombinant Viruses ◽  
Naturally Occurring ◽  
Age Related ◽  
Virus Excretion ◽  
Antibody Titers

A series of trials was conducted in which wild-type A/USSR/90/77 (H1N1) influenza A virus and a few of its antigenic variants were inoculated into volunteers. Infections readily occurred in people of all ages who had initial low antibody titers, but clinical effects were generally mild in comparison with those of the previously tested subtypes, H0N1, H1N1, H2N2, H3N2. There was, however, an inverse relationship between severity of symptoms and age of volunteers, although the incidence of virus excretion and of increase in anti-hemagglutinin was apparently not age related. Naturally occurring recombinant viruses with H3 hemagglutinin and one or more genes of A/USSR/098/77-like strains were likewise studied in volunteers. These clones also produced mild symptoms, providing evidence of an attenuating effect on H3N2 viruses by the substitution of some of its genes with the genes of an H1N1 virus.

scholarly journals Immunogenicity and Protection Efficacy of Replication-Deficient Influenza A Viruses with Altered NS1 Genes

2004 ◽  
Vol 78 (23) ◽  
pp. 13037-13045 ◽  
Author(s):  
Boris Ferko ◽  
Jana Stasakova ◽  
Julia Romanova ◽  
Christian Kittel ◽  
Sabine Sereinig ◽  
...  
Keyword(s):  
Influenza A ◽  
Rna Binding ◽  
T Cell Response ◽  
Binding Domain ◽  
Wild Type Virus ◽  
Type Virus ◽  
Ns1 Protein ◽  
Wild Type ◽  
Influenza A Viruses ◽  
Rna Binding Domain

ABSTRACT We explored the immunogenic properties of influenza A viruses with altered NS1 genes (NS1 mutant viruses). NS1 mutant viruses expressing NS1 proteins with an impaired RNA-binding function or insertion of a longer foreign sequence did not replicate in murine lungs but still were capable of inducing a Th1-type immune response resulting in significant titers of virus-specific serum and mucosal immunoglobulin G2 (IgG2) and IgA, but with lower titers of IgG1. In contrast, replicating viruses elicited high titers of serum and mucosal IgG1 but less serum IgA. Replication-deficient NS1 mutant viruses induced a rapid local release of proinflammatory cytokines such as interleukin-1β (IL-1β) and IL-6. Moreover, these viruses also elicited markedly higher levels of IFN-α/β in serum than the wild-type virus. Comparable numbers of virus-specific primary CD8+ T cells were determined in all of the groups of immunized mice. The most rapid onset of the recall CD8+-T-cell response upon the wild-type virus challenge was detected in mice primed with NS1 mutant viruses eliciting high levels of cytokines. It is noteworthy that there was one NS1 mutant virus encoding NS1 protein with a deletion of 40 amino acids predominantly in the RNA-binding domain that induced the highest levels of IFN-α/β, IL-6 and IL-1β after infection. Mice that were immunized with this virus were completely protected from the challenge infection. These findings indicate that a targeted modification of the RNA-binding domain of the NS1 protein is a valuable technique to generate replication-deficient, but immunogenic influenza virus vaccines.

scholarly journals The microRNA-let-7b-mediated attenuated strain of influenza A (H1N1) virus in a mouse model

2016 ◽  
Vol 10 (09) ◽  
pp. 973-981 ◽  
Author(s):  
Mingming Tan ◽  
Wenkui Sun ◽  
Chunlai Feng ◽  
Di Xia ◽  
Xiaoyue Shen ◽  
...  
Keyword(s):  
Mouse Model ◽  
Influenza A ◽  
Animal Studies ◽  
H1n1 Virus ◽  
Lethal Dose ◽  
Influenza Viruses ◽  
Wild Type Virus ◽  
Wild Type ◽  
Tnf Α ◽  
Influenza A H1n1

Introduction: Evaluating the attenuation of influenza viruses in animal studies is important in developing safe and effective vaccines. This study aimed to demonstrate that the microRNA (miRNA)-let-7b-mediated attenuated influenza viruses (miRT-H1N1) are sufficiently attenuated and safe in mice. Methodology: The pathogenicity of the miRT-H1N1virus was investigated in a mouse model, evaluated with median lethal dose (LD50). The replicative dynamics of the miRT-H1N1, wild type (wt)-H1N1, and scramble (scbl)-H1N1 viruses in the lungs of infected mice were compared. The degrees of lesions and the expression levels of IL-6, TNF-α, and IFN-β in the lungs of mice infected with different viruses were also analyzed. Results: In miRT-H1N1 virus-infected mice, 100% of mice survived, and a lower pathogenicity was characterized with non-significant weight loss when compared to mice infected with the control wt virus. The miRT-H1N1 virus was not fatal for mice, even at the highest dose administered. The viral load in the lungs of miRT-H1N1-infected mice was significantly lower than that of the wild-type virus-infected mice. Fewer pulmonary lesions and lower levels of selected pro-inflammatory cytokines in the lungs of the mice infected with the miRT-H1N1 virus were also observed. The virulence of the miRT-H1N1 virus reduced significantly, suggesting that the miRT-H1N1 virus was safe for mice. Conclusions: Our study demonstrated that the miRNA-mediated gene silencing is an alternative approach to attenuating the pathogenicity of wt influenza viruses that have potential in the development of influenza vaccines.

scholarly journals Multi-spectral fluorescent reporter influenza viruses (Color-flu) as powerful tools for in vivo studies

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Satoshi Fukuyama ◽  
Hiroaki Katsura ◽  
Dongming Zhao ◽  
Makoto Ozawa ◽  
Tomomi Ando ◽  
...  
Keyword(s):  
Influenza A ◽  
Fluorescent Proteins ◽  
Virus Antigen ◽  
Influenza Viruses ◽  
In Vivo Studies ◽  
Live Cells ◽  
Influenza A Viruses ◽  
Fluorescent Reporter ◽  
Viral Spread

Abstract Seasonal influenza A viruses cause annual epidemics of respiratory disease; highly pathogenic avian H5N1 and the recently emerged H7N9 viruses cause severe infections in humans, often with fatal outcomes. Although numerous studies have addressed the pathogenicity of influenza viruses, influenza pathogenesis remains incompletely understood. Here we generate influenza viruses expressing fluorescent proteins of different colours (‘Color-flu’ viruses) to facilitate the study of viral infection in in vivo models. On adaptation to mice, stable expression of the fluorescent proteins in infected animals allows their detection by different types of microscopy and by flow cytometry. We use this system to analyse the progression of viral spread in mouse lungs, for live imaging of virus-infected cells, and for differential gene expression studies in virus antigen-positive and virus antigen-negative live cells in the lungs of Color-flu-infected mice. Collectively, Color-flu viruses are powerful tools to analyse virus infections at the cellular level in vivo to better understand influenza pathogenesis.

scholarly journals Generation of Influenza A Viruses with Chimeric (Type A/B) Hemagglutinins

2003 ◽  
Vol 77 (14) ◽  
pp. 8031-8038 ◽  
Author(s):  
Taisuke Horimoto ◽  
Ayato Takada ◽  
Kiyoko Iwatsuki-Horimoto ◽  
Masato Hatta ◽  
Hideo Goto ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Influenza A ◽  
Reverse Genetics ◽  
Lethal Dose ◽  
Type A ◽  
Influenza Viruses ◽  
Type B ◽  
Wild Type ◽  
Influenza A Viruses ◽  
Contributing Factors

ABSTRACT To gain insight into the intertypic incompatibility between type A and B influenza viruses, we focused on the hemagglutinin (HA) gene, systematically studying the compatibility of chimeric (type A/B) HAs with a type A genetic background. An attempt to generate a reassortant containing an intact type B HA segment in a type A virus background by reverse genetics was unsuccessful despite transcription of the type B HA segment by the type A polymerase complex. Although a type A virus with a chimeric HA segment comprising the entire coding sequence of the type B HA flanked by the noncoding sequence of the type A HA was viable, it replicated only marginally. Other chimeric viruses contained type A/B HAs possessing the type A noncoding region together with either the signal peptide or transmembrane/cytoplasmic region of type A virus or both, with the remaining regions derived from the type B HA. Each of these viruses grew to median tissue culture infectious doses of more than 105 per ml, but those with more type A HA regions replicated better, suggesting protein-protein interactions or increased HA segment incorporation into virions as contributing factors in the efficient growth of this series of viruses. All of these chimeric (A/B) HA viruses were attenuated in mice compared with wild-type A or B viruses. All animals intranasally immunized with a chimeric virus survived upon challenge with a lethal dose of wild-type type B virus. These results suggest a framework for the design of a novel live vaccine virus.

scholarly journals The Development and Use of Reporter Influenza B Viruses

Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 736 ◽  
Author(s):  
Rebekah E. Dumm ◽  
Nicholas S. Heaton
Keyword(s):  
Immune Responses ◽  
Host Response ◽  
Influenza A ◽  
Genetically Modified ◽  
Viral Proteins ◽  
Influenza Viruses ◽  
Influenza B ◽  
Human Influenza ◽  
Influenza A Viruses ◽  
Viral Spread

Influenza B viruses (IBVs) are major contributors to total human influenza disease, responsible for ~1/3 of all infections. These viruses, however, are relatively less studied than the related influenza A viruses (IAVs). While it has historically been assumed that the viral biology and mechanisms of pathogenesis for all influenza viruses were highly similar, studies have shown that IBVs possess unique characteristics. Relative to IAV, IBV encodes distinct viral proteins, displays a different mutational rate, has unique patterns of tropism, and elicits different immune responses. More work is therefore required to define the mechanisms of IBV pathogenesis. One valuable approach to characterize mechanisms of microbial disease is the use of genetically modified pathogens that harbor exogenous reporter genes. Over the last few years, IBV reporter viruses have been developed and used to provide new insights into the host response to infection, viral spread, and the testing of antiviral therapeutics. In this review, we will highlight the history and study of IBVs with particular emphasis on the use of genetically modified viruses and discuss some remaining gaps in knowledge that can be addressed using reporter expressing IBVs.

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