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Influenza A H5N1 (Avian Flu) Hemagglutinin, HA ELISA Kit

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[#DEIA250] Influenza A H5N1 (Avian Flu) Hemagglutinin, HA ELISA Kit


DEIA250 | Influenza A H5N1 (Avian Flu) Hemagglutinin, HA ELISA Kit, 5 plates
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(1) Glycosylation and an amino acid insertion in the head of hemagglutinin independently affect the antigenic properties of H5N1 avian influenza viruses.[TOP]

Pubmed ID :30515728
Publication Date : //
Antigenic drift forces us to frequently update influenza vaccines; however, the genetic basis for antigenic variation remains largely unknown. In this study, we used clade 7.2 H5 viruses as models to explore the molecular determinants of influenza virus antigenic variation. We generated eight monoclonal antibodies (MAbs) targeted to the hemagglutinin (HA) protein of the index virus A/chicken/Shanxi/2/2006 and found that two representative antigenically drifted clade 7.2 viruses did not react with six of the eight MAbs. The E131N mutation and insertion of leucine at position 134 in the HA protein of the antigenically drifted strains eliminated the reactivity of the virus with the MAbs. We also found that the amino acid N131 in the H5 HA protein is glycosylated. Our results provide experimental evidence that glycosylation and an amino acid insertion or deletion in HA influence antigenic variation.

Authors : Gu Chunyang, Zeng Xianying, Song Yangming, Li Yanbing, Liu Liling, Kawaoka Yoshihiro, Zhao Dongming, Chen Hualan,

(2) Chimaeric Rift Valley fever virus-like particle vaccine candidate production in Nicotiana benthamiana.[TOP]

Pubmed ID :30488669
Publication Date : //
Rift valley fever virus (RVFV) is an emerging mosquito borne virus and haemorrhagic fever agent, which causes abortion storms in farmed small ruminants and potentially causes miscarriages in humans. Although live-attenuated vaccines are available for animals, they can only be used in endemic areas and there are currently no commercially available vaccines for humans. Here we describe the production of chimaeric RVFV virus-like particles transiently expressed in Nicotiana benthamiana by Agrobacterium tumefaciens-mediated gene transfer. The glycoprotein (Gn) gene was modified by removing its ectodomain (Gne) and fusing it to the transmembrane domain and cytosolic tail-encoding region of avian influenza H5N1 haemagglutinin. This was expressed transiently in N. benthamiana with purified protein yields calculated to be ∼ 57 mg/kg fresh weight. Transmission electron microscopy showed putative chimaeric RVFV Gne-HA particles of 49-60 nm which were immunogenic, eliciting Gn-specific antibody responses in vaccinated mice without the use of adjuvant. To our knowledge, this is the first demonstration of the synthesis of Gne-HA chimaeric RVFV VLPs and the first demonstration of a detectable yield of RVFV Gn in plants.

Authors : Mbewana Sandiswa, Meyers Ann E, Rybicki Edward P,

(3) Intravenous pathogenicity of influenza virus A/H5N1/2014 isolated from pig in Ogbomoso, Nigeria.[TOP]

Pubmed ID :30483460
Publication Date : //
Understanding the pathogenicity of avian influenza viruses in poultry is an important scientific and public health challenge because of antigenic shift/drift and a source of novel, potentially human-pathogenic strains. We have previously isolated an influenza A strain (H5N1/2014/Ogbomoso) from an outbreak among pig and have now aimed to assess its pathogenicity in an avian host and to categorize it as a low or high pathogenic strain. Intravenous pathogenicity index of the isolated virus was assayed using experimental infection of 6 weeks old pathogen-specific free chicken. The peak of clinical signs was on day three post-infection, and one death was observed on day eight. The intravenous pathogenicity index of this isolate was 0.08. This results classify this isolate as a low pathogenic avian influenza strain.

Authors : Oladipo E Kolawole, Oloke J Kola, Adeniji J Adekunle,

(4) Efficient inhibition of avian and seasonal influenza A viruses by a virus-specific Dicer-substrate siRNA swarm in human monocyte-derived macrophages and dendritic cells.[TOP]

Pubmed ID :30463970
Publication Date : //
Influenza A viruses (IAVs) are viral pathogens that cause epidemics and occasional pandemics of significant mortality. The generation of efficacious vaccines and antiviral drugs remains a challenge due to the rapid appearance of new influenza types and antigenic variants. Consequently, novel strategies for the prevention and treatment of IAV infections are needed given the limitations of the presently available antivirals. Here, we used enzymatically produced IAV-specific double-stranded RNA (dsRNA) molecules and Dicer for the generation of a swarm of small interfering RNA (siRNA) molecules. The siRNAs target multiple conserved genomic regions of the IAVs. In mammalian cells, the produced 25-27 nucleotide long siRNA molecules are processed by endogenous Dicer into 21-nucleotide siRNAs and are thus designated as Dicer-substrate siRNAs (DsiRNAs). We evaluated the efficacy of the above DsiRNA swarm at preventing IAV infections in human primary monocyte-derived macrophages and dendritic cells. The replication of different IAV strains, including avian influenza H5N1 and H7N9 viruses, was significantly inhibited by pre-transfection of the cells with the IAV-specific DsiRNA swarm. Up to 7 orders of magnitude inhibition of viral RNA expression was observed, which led to a dramatic inhibition of IAV protein synthesis and virus production. The IAV-specific DsiRNA swarm inhibited virus replication directly through the RNA interference pathway although a weak induction of innate interferon responses was detected. Our results provide direct evidence for the feasibility of the siRNA strategy and the potency of DsiRNA swarms in the prevention and treatment of influenza, including the highly pathogenic avian influenza viruses. In spite of the enormous amount of research, influenza virus is still one of the major challenges for medical virology due to its capacity to generate new variants, which potentially lead to severe epidemics and pandemics. We demonstrated here that a swarm of small interfering RNA (siRNA) molecules, including more than one hundred different antiviral RNA molecules targeting the most conserved regions of influenza A virus genome, could efficiently inhibit the replication of all tested avian and seasonal influenza A variants in human primary monocyte-derived macrophages and dendritic cells. The wide antiviral spectrum makes the virus-specific siRNA swarm a potentially efficient treatment modality against both avian and seasonal influenza viruses.

Authors : Jiang Miao, Österlund Pamela, Westenius Veera, Guo Deyin, Poranen Minna M, Bamford Dennis H, Julkunen Ilkka,

(5) Genetic compatibility of reassortants between avian H5N1 and H9N2 influenza viruses with higher pathogenicity in mammals.[TOP]

Pubmed ID :30463961
Publication Date : //
The co-circulation of H5N1 and H9N2 avian influenza viruses in birds in Egypt provides reassortment opportunities between these two viruses. However, little is known about the emergence potential of reassortants derived from Egyptian H5N1 and H9N2 viruses and about the biological properties of such reassortants. To evaluate the potential public health risk of reassortants of these viruses, we used reverse genetics to generate the 63 possible reassortants derived from contemporary Egyptian H5N1 and H9N2 viruses, containing the H5N1 surface gene segments and combinations of the H5N1 and H9N2 internal gene segments, and analyzed their genetic compatibility, replication ability and virulence in mice. Genes in the reassortants showed remarkably high compatibility. Replication of most reassortants was higher than the parental H5N1 virus in human cells. Six reassortants were thought to emerge in birds under neutral or positive selective pressure, and four of them had higher pathogenicity than the parental H5N1 and H9N2 viruses. Our results indicated that H5N1-H9N2 reassortants could be transmitted efficiently to mammals with significant public health risk if they emerge in Egypt, although the viruses might not emerge frequently in birds.Close interaction between avian influenza (AI) viruses and humans in Egypt appears to have resulted in many of the worldwide cases of human infections by both H5N1 and H9N2 AI viruses. Egypt is regarded as a hot spot of AI virus evolution. Although no natural reassortant of H5N1 and H9N2 AI viruses has been reported so far, their co-circulation in Egypt may allow emergence of reassortants that may present a significant public health risk. Using reverse genetics, we report here the first comprehensive data showing that H5N1-N9N2 reassortants have fairly high genetic compatibility and possibly higher pathogenicity in mammals, including humans, than the parental viruses. Our results provide insight into the emergence potential of avian H5N1-H9N2 reassortants that may pose a high public health risk.

Authors : Arai Yasuha, Ibrahim Madiha S, Elgendy Emad M, Daidoji Tomo, Ono Takao, Suzuki Yasuo, Nakaya Takaaki, Matsumoto Kazuhiko, Watanabe Yohei,

(6) H5N1 Influenza a Virus Replicates Productively in Pancreatic Cells and Induces Apoptosis and Pro-Inflammatory Cytokine Response.[TOP]

Pubmed ID :30460207
Publication Date : //
The inflammatory response and apoptosis have been proved to have a crucial role in the pathogenesis of the influenza A virus (IAV). Previous studies indicated that while IAV commonly causes pancreatitis and pancreatic damage in naturally and experimentally infected animals, the molecular mechanisms of the pathogenesis of IAV infection are less reported. In the present study, we showed for the first time that both avian-like (α-2,3-linked) and human-like (α-2,6-linked) sialic acid (SA) receptors were expressed by the mouse pancreatic cancer cell line PAN02 and the human pancreatic cancer cell line PANC-1. Using growth kinetics experiments, we also showed that PAN02 and PANC-1 cells supported the productive replication of the H5N1 highly pathogenic avian influenza while exhibited the limited replication of IAV subtypes H1N1 and H7N2 . The infection of H5N1 in pancreatic cells was confirmed by the histopathological and immunohistochemical staining of pancreas tissue from mice. Other than H1N1 and H7N2, severe damage and extensive positive signals were observed in pancreas of H5N1 infected mice. All three virus subtypes induced apoptosis but also triggered the infected PAN02 and PANC-1 cells to release pro-inflammatory cytokines and chemokines including interferon (IFN)-α, IFN-β, IFN-γ, chemokine (C-C motif) ligand 2 (CCL2), tumor necrosis factor (TNF)-α, and interleukin (IL)-6. Notably, the subtypes of H5N1 could significantly upregulate these cytokines and chemokines in both two cells when compared with H1N1 and H7N2. The present data provide further understanding of the pathogenesis of H5N1 IAV in pancreatic cells derived from humans and mammals and may also benefit the development of new treatment against H5N1 influenza virus infection.

Authors : Huo Caiyun, Xiao Kai, Zhang Shouping, Tang Yuling, Wang Ming, Qi Peng, Xiao Jin, Tian Haiyan, Hu Yanxin,

(7) Characterising routes of H5N1 and H7N9 spread in China using Bayesian phylogeographical analysis.[TOP]

Pubmed ID :30459301
Publication Date : //
Avian influenza H5N1 subtype has caused a global public health concern due to its high pathogenicity in poultry and high case fatality rates in humans. The recently emerged H7N9 is a growing pandemic risk due to its sustained high rates of human infections, and recently acquired high pathogenicity in poultry. Here, we used Bayesian phylogeography on 265 H5N1 and 371 H7N9 haemagglutinin sequences isolated from humans, animals and the environment, to identify and compare migration patterns and factors predictive of H5N1 and H7N9 diffusion rates in China. H7N9 diffusion dynamics and predictor contributions differ from H5N1. Key determinants of spatial diffusion included: proximity between locations (for H5N1 and H7N9), and lower rural population densities (H5N1 only). For H7N9, additional predictors included low avian influenza vaccination rates, low percentage of nature reserves and high humidity levels. For both H5N1 and H7N9, we found viral migration rates from Guangdong to Guangxi and Guangdong to Hunan were highly supported transmission routes (Bayes Factor > 30). We show fundamental differences in wide-scale transmission dynamics between H5N1 and H7N9. Importantly, this indicates that avian influenza initiatives designed to control H5N1 may not be sufficient for controlling the H7N9 epidemic. We suggest control and prevention activities to specifically target poultry transportation networks between Central, Pan-Pearl River Delta and South-West regions.

Authors : Bui Chau M, Adam Dillon C, Njoto Edwin, Scotch Matthew, MacIntyre C Raina,

(8) Satellite telemetry tracks flyways of Asian Openbill storks in relation to H5N1 avian influenza spread and ecological change.[TOP]

Pubmed ID :30445946
Publication Date : //
Asian Openbills, Anastomus oscitans, have long been known to migrate from South to Southeast Asia for breeding and nesting. In Thailand, the first outbreak of H5N1 highly pathogenic avian influenza (HPAI) infection in the Openbills coincided with the outbreak in the poultry. Therefore, the flyways of Asian Openbills was determined to study their role in the spread of H5N1 HPAI virus to poultry and wild birds, and also within their flocks.

Authors : Ratanakorn Parntep, Suwanpakdee Sarin, Wiriyarat Witthawat, Eiamampai Krairat, Chaichoune Kridsada, Wiratsudakul Anuwat, Sariya Ladawan, Puthavathana Pilaipan,

(9) A neuraminidase activity-based microneutralization assay for evaluating antibody responses to influenza H5 and H7 vaccines.[TOP]

Pubmed ID :30440054
Publication Date : //
Outbreaks of the highly pathogenic avian influenza H5N1 and H7N9 viruses have spurred an unprecedented research effort to develop antivirals and vaccines against influenza. Standardized methods for vaccine evaluation are critical for facilitating vaccine development. Compared with hemagglutination inhibition assays, mounting evidence suggest that microneutralization tests (MNTs) is a better choice for the evaluation of candidate pandemic influenza vaccines because they measure neutralizing antibody activity in cell cultures and are more sensitive in detecting H5 and H7. Here, we report a MNT measuring neuraminidase activity as the read-out (NA-MNT) for quantitative analysis of neutralizing antibodies against avian influenza viruses. Compared to the conventional microneutralization assay (ELISA-MNT), the NA-MNT is faster with lower intra- and inter-assay variations, while no difference in geometric mean titers was found between these two assays for the evaluation of H5N1 and H7N9 vaccines. These results suggest that NA-MNT is a reliable and high throughput method which could facilitate the development of candidate pandemic influenza vaccine.

Authors : Zhao Hui, Xu Kangwei, Jiang Zheng, Shao Ming, Liu Shuzhen, Li Xuguang, Wang Junzhi, Li Changgui,

(10) Pandemic influenza preparedness in the WHO African region: are we ready yet?[TOP]

Pubmed ID :30428846
Publication Date : //
Prior to the 2009 pandemic H1N1, and the unprecedented outbreak of Highly Pathogenic Avian Influenza (HPAI) caused by the H5N1 virus, the World Health Organization (WHO) called upon its Member States to develop preparedness plans in response to a new pandemic in humans. The WHO Member States responded to this call by developing national pandemic plans in accordance with the International Health Regulations (IHR) to strengthen the capabilities of Member States to respond to different pandemic scenarios. In this study, we aim to evaluate the quality of the preparedness plans in the WHO African region since their inception in 2005.

Authors : Sambala Evanson Z, Kanyenda Tiwonge, Iwu Chinwe Juliana, Iwu Chidozie Declan, Jaca Anelisa, Wiysonge Charles S,