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

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.

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Distribution of influenza viruses in Northern Greece during 1972–1983

Journal of Hygiene ◽

10.1017/s0022172400064780 ◽

1984 ◽

Vol 93 (2) ◽

pp. 263-267 ◽

Cited By ~ 4

Author(s):

V. Kyriazopoulou-Dalaina

Keyword(s):

Time Scale ◽

Influenza A ◽

World Wide ◽

Type A ◽

Influenza Viruses ◽

Influenza B ◽

Type B ◽

Influenza A Viruses ◽

Northern Greece

SummaryObservations on the circulation of influenza viruses in Northern Greece during the winters of 1972/3 to 1982/3 are presented.Influenza A viruses were detected every winter with the exception of those of 1973/4 and 1981/2, when neither type A nor type B was isolated. The strains of type A isolated during the study period were similar to those circulating world-wide over the same time scale.Influenza B viruses were isolated only during the winters of 1972/3 and 1979/80; influenza A viruses were also circulating in the community at those times. The B strains detected were similar to those recorded world-wide during the period of study.

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IDENTIFICATION OF INFLUENZA VIRUSES IN HUMAN AND POULTRY IN THE AREA OF LARANGAN WET MARKET SIDOARJO-EAST JAVA, INDONESIA

Indonesian Journal of Tropical and Infectious Disease ◽

10.20473/ijtid.v4i4.230 ◽

2013 ◽

Vol 4 (4) ◽

pp. 30

Author(s):

Edith Frederika ◽

Aldise Mareta ◽

Djoko Poetranto ◽

Laksmi Wulandari ◽

Retno Asih Setyoningrum ◽

...

Keyword(s):

Influenza Virus ◽

Virus Type ◽

Influenza A ◽

Type A ◽

Influenza Viruses ◽

Nasopharyngeal Swab ◽

Type B ◽

Influenza A Viruses ◽

Type C ◽

Wet Market

Background: Influenza is a viral infection that attacks the respiratory system (nose, throat, and lungs) that commonly known as “flu”. There are 3 types of influenza viruses, such as type A, type B, and type C. Influenza virus type A is the type of virus that can infect both human and animals, virus type B are normally found only in human, and Influenza virus type C can cause mild illness in human and not causing any epidemics or pandemics. Among these 3 types of influenza viruses, only influenza A viruses infect birds, particularly wild bird that are the natural host for all subtypes of influenza A virus. Generally, those wild birds do not get sick when they are infected with influenza virus, unlike chickens or ducks which may die from avian influenza. Aim: In this study, we are identifying the influenza viruses among poultry in Larangan wet market. Method: Around 500 kinds of poultry were examined from cloacal swab. Result: Those samples were restrained with symptoms of suspected H5. The people who worked as the poultry-traders intact with the animal everyday were also examined, by taking nasopharyngeal swab and blood serum. Conclusion: Identification of influenza viruses was obtained to define the type and subtype of influenza virus by PCR.

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

mSphere ◽

10.1128/msphere.00052-21 ◽

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.

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Strain-dependent effects of PB1-F2 of triple-reassortant H3N2 influenza viruses in swine

Journal of General Virology ◽

10.1099/vir.0.045005-0 ◽

2012 ◽

Vol 93 (10) ◽

pp. 2204-2214 ◽

Cited By ~ 20

Author(s):

Lindomar Pena ◽

Amy L. Vincent ◽

Crystal L. Loving ◽

Jamie N. Henningson ◽

Kelly M. Lager ◽

...

Keyword(s):

Virus Replication ◽

Influenza A ◽

Reverse Genetics ◽

Influenza Viruses ◽

Dependent Manner ◽

Lung Pathology ◽

Influenza A Viruses ◽

Virus Shedding ◽

The Impact ◽

Strain Dependent

The PB1-F2 protein of the influenza A viruses (IAVs) can act as a virulence factor in mice. Its contribution to the virulence of IAV in swine, however, remains largely unexplored. In this study, we chose two genetically related H3N2 triple-reassortant IAVs to assess the impact of PB1-F2 in virus replication and virulence in pigs. Using reverse genetics, we disrupted the PB1-F2 ORF of A/swine/Wisconsin/14094/99 (H3N2) (Sw/99) and A/turkey/Ohio/313053/04 (H3N2) (Ty/04). Removing the PB1-F2 ORF led to increased expression of PB1-N40 in a strain-dependent manner. Ablation of the PB1-F2 ORF (or incorporation of the N66S mutation in the PB1-F2 ORF, Sw/99 N66S) affected the replication in porcine alveolar macrophages of only the Sw/99 KO (PB1-F2 knockout) and Sw/99 N66S variants. The Ty/04 KO strain showed decreased virus replication in swine respiratory explants, whereas no such effect was observed in Sw/99 KO, compared with the wild-type (WT) counterparts. In pigs, PB1-F2 did not affect virus shedding or viral load in the lungs for any of these strains. Upon necropsy, PB1-F2 had no effect on the lung pathology caused by Sw/99 variants. Interestingly, the Ty/04 KO-infected pigs showed significantly increased lung pathology at 3 days post-infection compared with pigs infected with the Ty/04 WT strain. In addition, the pulmonary levels of interleukin (IL)-6, IL-8 and gamma interferon were regulated differentially by the expression of PB1-F2. Taken together, these results indicate that PB1-F2 modulates virus replication, virulence and innate immune responses in pigs in a strain-dependent fashion.

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VirPreNet: A weighted ensemble convolutional neural network for the virulence prediction of influenza A virus using all 8 segments

10.1101/2020.07.31.230904 ◽

2020 ◽

Author(s):

Rui Yin ◽

Zihan Luo ◽

Pei Zhuang ◽

Zhuoyi Lin ◽

Chee Keong Kwoh

Keyword(s):

Public Health ◽

Neural Network ◽

Convolutional Neural Network ◽

Influenza A Virus ◽

Influenza A ◽

Lethal Dose ◽

Influenza Viruses ◽

Numerical Representation ◽

Influenza A Viruses ◽

Linear Layer

AbstractMotivationInfluenza viruses are persistently threatening public health, causing annual epidemics and sporadic pandemics. The evolution of influenza viruses remains to be the main obstacle in the effectiveness of antiviral treatments due to rapid mutations. Previous work has been investigated to reveal the determinants of virulence of the influenza A virus. To further facilitate flu surveillance, explicit detection of influenza virulence is crucial to protect public health from potential future pandemics.ResultsIn this paper, we propose a weighted ensemble convolutional neural network for the virulence prediction of influenza A viruses named VirPreNet that uses all 8 segments. Firstly, mouse lethal dose 50 is exerted to label the virulence of infections into two classes, namely avirulent and virulent. A numerical representation of amino acids named ProtVec is applied to the 8-segments in a distributed manner to encode the biological sequences. After splittings and embeddings of influenza strains, the ensemble convolutional neural network is constructed as the base model on the influenza dataset of each segment, which serves as the VirPreNet’s main part. Followed by a linear layer, the initial predictive outcomes are integrated and assigned with different weights for the final prediction. The experimental results on the collected influenza dataset indicate that VirPreNet achieves state-of-the-art performance combining ProtVec with our proposed architecture. It outperforms baseline methods on the independent testing data. Moreover, our proposed model reveals the importance of PB2 and HA segments on the virulence prediction. We believe that our model may provide new insights into the investigation of influenza [email protected] and ImplementationCodes and data to generate the VirPreNet are publicly available at https://github.com/Rayin-saber/VirPreNet

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Establishment of Vero cell RNA polymerase I-driven reverse genetics for Influenza A virus and its application for pandemic (H1N1) 2009 influenza virus vaccine production

Journal of General Virology ◽

10.1099/vir.0.051284-0 ◽

2013 ◽

Vol 94 (6) ◽

pp. 1230-1235 ◽

Cited By ~ 12

Author(s):

Min-Suk Song ◽

Yun Hee Baek ◽

Philippe Noriel Q. Pascua ◽

Hyeok-il Kwon ◽

Su-Jin Park ◽

...

Keyword(s):

Vero Cell ◽

Influenza A ◽

Reverse Genetics ◽

Vero Cells ◽

Influenza Virus Vaccine ◽

Influenza Viruses ◽

Vaccine Production ◽

Influenza A Viruses ◽

Alternative Means ◽

Polymerase I

The constant threat of newly emerging influenza viruses with pandemic potential requires the need for prompt vaccine production. Here, we utilized the Vero cell polymerase I (PolI) promoter, rather than the commonly used human PolI promoter, in an established reverse-genetics system to rescue viable influenza viruses in Vero cells, an approved cell line for human vaccine production. The Vero PolI promoter was more efficient in Vero cells and demonstrated enhanced transcription levels and virus rescue rates commensurate with that of the human RNA PolI promoter in 293T cells. These results appeared to be associated with more efficient generation of A(H1N1)pdm09- and H5N1-derived vaccine seed viruses in Vero cells, whilst the rescue rates in 293T cells were comparable. Our study provides an alternative means for improving vaccine preparation by using a novel reverse-genetics system for generating influenza A viruses.

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

Journal of General Virology ◽

10.1099/vir.0.80991-0 ◽

2005 ◽

Vol 86 (10) ◽

pp. 2817-2821 ◽

Cited By ~ 36

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.

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Age and secular distributions of virus-proven influenza patients in successive epidemics 1961–1976 in Cirencester: Epidemiological significance discussed

Journal of Hygiene ◽

10.1017/s0022172400064548 ◽

1984 ◽

Vol 92 (3) ◽

pp. 303-336 ◽

Cited By ~ 10

Author(s):

R. E. Hope-Simpson

Keyword(s):

Influenza A ◽

Age Distribution ◽

Type A ◽

Incidence Rates ◽

Influenza Viruses ◽

High Rate ◽

Type B ◽

Practice Population ◽

Laboratory Surveillance ◽

Age Patterns

SummaryA general practice population of around 3900, under continuous clinical and laboratory surveillance, experienced 20 outbreaks of influenza between March 1960 and March 1976. Four epidemics were caused by subtype H2N2 type A viruses, seven by subtype H3N2 type A viruses and nine outbreaks by type B viruses. The age of every person proved virologically to have influenza is related to the age structure of the community and to the phase of the epidemic in which the virus-positive specimens were collected. Children 0–15 years old suffered a higher incidence rate than adults 16–90±. Pre-school children 0–4 suffered the highest rate of infection by viruses of both influenza A subtypes, whereas older schoolchildren 10–15 suffered the highest rate of type B infections. Despite these high incidence rates neither pre-school nor schoolchildren appear to have been the major disseminators of any of these influenza viruses in the community.Adults of all ages suffered a high rate of infection even into extreme old age, and the indiscriminate age distribution among adults was sustained in the successive epidemics. Such age-patterns are not those caused by a highly infectious immunizing virus surviving by means of direct transmissions from the sick, whose prompt development of the disease continues endless chains of transmissions. An alternative epidemic mechanism – whereby the virus does not spread from the sick but becomes latent in them, reactivating seasonally so that they later infect their companions – would produce age patterns similar to those recorded here for influenza patients. The suggested mechanism is illustrated by a simple conceptual model and the influenzal age patterns are discussed in relation to the recycling of influenza A subtypes.

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Replication competent, 10-segmented influenza viruses as antiviral therapeutics

10.1101/547059 ◽

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.

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Genetic relationship between the HA genes of type A influenza viruses isolated in off-seasons and later epidemic seasons

Epidemiology and Infection ◽

10.1017/s0950268800048536 ◽

1991 ◽

Vol 106 (2) ◽

pp. 383-395 ◽

Cited By ~ 11

Author(s):

S. Nakajima ◽

K. Nakamura ◽

F. Nishikawa ◽

K. Nakajima

Keyword(s):

Phylogenetic Tree ◽

Genetic Relationship ◽

Influenza A ◽

Type A ◽

Influenza Viruses ◽

Gene Sequences ◽

Influenza A Viruses ◽

Ha Gene ◽

Influenza A H1n1

SUMMARYFrom January 1985 to March 1989, off-season viruses of H1N1 and H3N2 subtypes of influenza A viruses were isolated on five occasions in Japan. The HA gene sequences of the influenza A(H1N1) and A(H3N2) viruses isolated in Japan from 1985–9 were analysed and the phylogenetic tree for each subtype virus was constructed to determine any genetic relationship between viruses isolated in off-seasons and the epidemic viruses of the following influenza seasons. In one instance with H1N1 viruses in 1986 and in two instances with H3N2 viruses in 1985 and 1987, the spring isolates were genetically close to some of the winter isolates and were considered to be the parental viruses of the following influenza seasons. However, even in these cases, influenza viruses of the same subtype with different lineages co-circulated in Japan.

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