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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

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DEIA250 | Influenza A H5N1 (Avian Flu) Hemagglutinin, HA ELISA Kit, 5 plates
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(1) The Vestigial Esterase Domain of Haemagglutinin of H5N1 Avian Influenza A Virus: Antigenicity and Contribution to Viral Pathogenesis.[TOP]

Pubmed ID :30103381
Publication Date : //
Initial attempts to develop monoclonal antibodies as therapeutics to resolve influenza infections focused mainly on searching for antibodies with the potential to neutralise the virus in vitro with classical haemagglutination inhibition and microneutralisation assays. This led to the identification of many antibodies that bind to the head domain of haemagglutinin (HA), which generally have potent neutralisation capabilities that block viral entry or viral membrane fusion. However, this class of antibodies has a narrow breadth of protection in that they are usually strain-specific. This led to the emphasis on stalk-targeting antibodies, which are able to bind a broad range of viral targets that span across different influenza subtypes. Recently, a third class of antibodies targeting the vestigial esterase (VE) domain have been characterised. In this review, we describe the key features of neutralising VE-targeting antibodies and compare them with head- and stalk-class antibodies.

Authors : Zheng Zhiqiang, Paul Subha Sankar, Mo Xiaobing, Yuan Yu-Ren Adam, Tan Yee-Joo,



(2) A Bovine Adenoviral Vector-Based H5N1 Influenza -Vaccine Provides Enhanced Immunogenicity and Protection at a Significantly Low Dose.[TOP]

Pubmed ID :30101154
Publication Date : //
Several human and nonhuman adenovirus (AdV) vectors including bovine AdV type 3 (BAdV-3) were developed as gene delivery vectors to supplement and/or elude human AdV (HAdV)-specific neutralizing antibodies (vector immunity). Here we evaluated the vaccine immunogenicity and efficacy of BAdV-3 vector (BAd-H5HA) expressing hemagglutinin (HA) of a H5N1 influenza virus in a dose escalation study in mice with the intranasal (IN) or intramuscular (IM) route of inoculation in comparison with the HAdV type C5 (HAdV-C5) vector (HAd-H5HA) expressing HA of a H5N1 influenza virus. Dose-related increases in the immune responses were clearly noticeable. A single IM inoculation with BAd-H5HA resulted in enhanced cellular immune responses compared with that of HAd-H5HA and conferred complete protection following challenge with a heterologous H5N1 virus at the dose of 3 × 10 plaque-forming units (PFUs), whereas a significant amount of influenza virus was detected in the lungs of mice immunized with 1 × 10 PFUs of HAd-H5HA. Similarly, compared with that of HAd-H5HA, a single IN inoculation with BAd-H5HA produced significantly enhanced humoral (HA-specific immunoglobulin [IgG] and its subclasses, as well as HA-specific IgA) and cellular immune responses, and conferred complete protection following challenge with a heterologous H5N1 virus. Complete protection with BAd-H5HA was observed with the lowest vaccine dose (1 × 10 PFUs), but similar protection with HAd-H5HA was observed at the highest vaccine dose (1 × 10 PFUs). These results suggest that at least 30-fold dose sparing can be achieved with BAd-H5HA vector compared with HAd-H5HA vaccine vector.

Authors : Sayedahmed Ekramy E, Hassan Ahmed O, Kumari Rashmi, Cao Weiping, Gangappa Shivaprakash, York Ian, Sambhara Suryaprakash, Mittal Suresh K,



(3) Substrate binding by the 2 sialic acid-binding site of influenza A virus N1 neuraminidase contributes to enzymatic activity.[TOP]

Pubmed ID :30089692
Publication Date : //
The influenza A virus (IAV) neuraminidase (NA) protein plays an essential role in the release of virus particles from cells and decoy receptors. The NA enzymatic activity presumably needs to match the activity of the IAV hemagglutinin (HA) attachment protein and the host sialic acid (SIA) receptor repertoire. We analyzed the enzymatic activities of N1 NA proteins derived from avian (H5N1) and human (H1N1) IAVs and analyzed the role of the 2 SIA-binding site, located adjacent to the conserved catalytic site, therein. SIA-contact residues in the 2 SIA-binding site of NA are highly conserved in avian, but not in human IAVs. All N1 proteins preferred cleaving α2,3- over α2,6-linked SIAs, even when their corresponding HA protein displayed a strict preference for α2,6-linked SIAs, indicating that the specificity of the NA protein does not need to fully match that of the corresponding HA protein. NA activity was affected by substitutions in the 2 SIA-binding site that are observed in avian and human IAVs, at least when multivalent rather than monovalent substrates were used. These mutations included both SIA-contact residues and residues that do not directly interact with SIA in all three loops of the 2 SIA-binding site. Substrate binding via the 2 SIA-binding site enhanced the catalytic activity of N1. Mutation of the 2 SIA-binding site was also shown to affect virus replication Our results indicate an important role for the N1 2 SIA-binding site in binding to and cleavage of multivalent substrates.Avian and human influenza A viruses (IAVs) preferentially bind α2,3- or α2,6-linked sialic acids (SIAs), respectively. A functional balance between the hemagglutinin (HA) attachment and neuraminidase (NA) proteins is thought to be important for host tropism. What this balance entails at the molecular level is, however, not well understood. We now show that N1 proteins of both avian and human viruses prefer cleaving avian- over human-type receptors, although human viruses were relatively better in cleavage of the human-type receptors. In addition, we show that substitutions at different positions in the 2 SIA-binding site found in NA proteins of human IAVs have a profound effect on binding and cleavage of multivalent, but not monovalent, receptors and affect virus replication. Our results indicate that the HA-NA balance can be tuned via modification of substrate binding via this site and suggest an important role of the 2 SIA-binding site in host tropism.

Authors : Du Wenjuan, Dai Meiling, Li Zeshi, Boons Geert-Jan, Peeters Ben, van Kuppeveld Frank J M, de Vries Erik, de Haan Cornelis A M,



(4) Heterosubtypic Protections against Human-Infecting Avian Influenza Viruses Correlate to Biased Cross-T-Cell Responses.[TOP]

Pubmed ID :30087171
Publication Date : //
Against a backdrop of seasonal influenza virus epidemics, emerging avian influenza viruses (AIVs) occasionally jump from birds to humans, posing a public health risk, especially with the recent sharp increase in H7N9 infections. Evaluations of cross-reactive T-cell immunity to seasonal influenza viruses and human-infecting AIVs have been reported previously. However, the roles of influenza A virus-derived epitopes in the cross-reactive T-cell responses and heterosubtypic protections are not well understood; understanding those roles is important for preventing and controlling new emerging AIVs. Here, among the members of a healthy population presumed to have previously been infected by pandemic H1N1 (pH1N1), we found that pH1N1-specific T cells showed cross- but biased reactivity to human-infecting AIVs, i.e., H5N1, H6N1, H7N9, and H9N2, which correlates with distinct protections. Through a T-cell epitope-based phylogenetic analysis, the cellular immunogenic clustering expanded the relevant conclusions to a broader range of virus strains. We defined the potential key conserved epitopes required for cross-protection and revealed the molecular basis for the immunogenic variations. Our study elucidated an overall profile of cross-reactivity to AIVs and provided useful recommendations for broad-spectrum vaccine development. We revealed preexisting but biased T-cell reactivity of pH1N1 influenza virus to human-infecting AIVs, which provided distinct protections. The cross-reactive T-cell recognition had a regular pattern that depended on the T-cell epitope matrix revealed via bioinformatics analysis. Our study elucidated an overall profile of cross-reactivity to AIVs and provided useful recommendations for broad-spectrum vaccine development.

Authors : Zhao Min, Liu Kefang, Luo Jiejian, Tan Shuguang, Quan Chuansong, Zhang Shuijun, Chai Yan, Qi Jianxun, Li Yan, Bi Yuhai, Xiao Haixia, Wong Gary, Zhou Jianfang, Jiang Taijiao, Liu Wenjun, Yu Hongjie, Yan Jinghua, Liu Yingxia, Shu Yuelong, Wu Guizhen, Wu Aiping, Gao George F, Liu William J,



(5) Therapeutic implications of human umbilical cord mesenchymal stromal cells in attenuating influenza A/H5N1-associated acute lung injury.[TOP]

Pubmed ID :30085072
Publication Date : //
Highly pathogenic avian influenza viruses can cause severe forms of acute lung injury (ALI) in humans, where pulmonary flooding leads to respiratory failure. Therapeutic benefits of bone-marrow mesenchymal stromal cells (BM-MSCs) have been demonstrated in an influenza H5N1 ALI model. However, clinical translation is impractical and limited by declining efficacy with increase in donor age. Umbilical cord MSCs (UC-MSCs) are easier to obtain in comparison, and their primitive source may offer more potent therapeutic effects.

Authors : Loy Hayley, Kuok Denise I T, Hui Kenrie P Y, Choi Miranda H L, Yuen W, Nicholls John M, Peiris J S Malik, Chan Michael C W,



(6) Glycan-masking hemagglutinin antigens from stable CHO cell clones for H5N1 avian influenza vaccine development.[TOP]

Pubmed ID :30080931
Publication Date : //
Refocusing of B cell responses can be achieved by preserving the overall fold of the antigen structure but selectively mutating the undesired antigenic sites with additional N-linked glycosylation motifs for glycan-masking the vaccine antigen. We previously reported that glycan-masking recombinant H5 hemagglutin (rH5HA) antigens on residues 83, 127, and 138 (g127+g138 or g83+g127+138 rH5HA) elicited broader neutralizing antibodies and protection against heterologous clades/subclades of high pathogenic avian influenza H5N1 viruses. In this study, we engineered the stably-expressing CHO cell clones for producing the glycan-masking g127+g138 and g83+g127+g138 rH5HA antigens. All of these glycan-masking rH5HA antigens produced in stable CHO cell clones were found to be mostly oligomeric structures. Only the immunization with the glycan-masking g127+g138 but not g83+g127+g138 rH5HA antigens elicited more potent neutralizing antibody titers against four out of five heterologous clades/subclades of H5N1 viral strains. The increased neutralizing antibody titers against these heterologous viral strains were correlated with the increased amounts of stem-binding antibodies, only the glycan-masking g127+g138 rH5HA antigens can translate into more protection against live viral challenges. The stable CHO cell line-produced glycan-masking g127+g138 rH5HA can be used for H5N1 subunit vaccine development. This article is protected by copyright. All rights reserved.

Authors : Chen Ting-Hsaun, Liu Wen-Chun, Lin Chia-Ying, Liu Chia-Cyi, Jan Jia-Tsrong, Spearman Maureen, Butler Michael, Wu Suh-Chin,



(7) Influenza A(H5N1) viruses with A(H9N2) single gene (matrix or PB1) reassortment isolated from Cambodian live bird markets.[TOP]

Pubmed ID :30075357
Publication Date : //
Live bird market surveillance for avian influenza viruses in Cambodia in 2015 has led to the detection of two 7:1 reassortant influenza A(H5N1) clade 2.3.2.1c viruses. These reassortant strains, designated A/duck/Cambodia/Z564W35M1/2015 and A/chicken/Cambodia/Z850W49M1/2015, both contained a single gene (PB1 and matrix gene, respectively) from concurrently circulating A(H9N2) influenza viruses. All other viral genes from both isolates clustered with A(H5N1) clade 2.3.2.1 viruses. Continued and prolonged co-circulation of influenza A(H5N1) and A(H9N2) viruses in Cambodian live bird markets may present a risk for the emergence of novel influenza reassortant viruses with negative agricultural and/or public health implications.

Authors : Suttie Annika, Karlsson Erik A, Deng Yi-Mo, Horm Srey Viseth, Yann Sokhoun, Tok Songha, Sorn San, Holl Davun, Tum Sothyra, Hurt Aeron C, Greenhill Andrew R, Barr Ian G, Horwood Paul F, Dussart Philippe,



(8) Sialic acid involves in the interaction between ovomucin and hemagglutinin and influences the antiviral activity of ovomucin.[TOP]

Pubmed ID :30071221
Publication Date : //
Ovomucin (OVM) plays an important role in inhibiting infection of various pathogens. However, this bioactivity mechanism is not much known. Here, the role of sialic acid in OVM anti-virus activity has been studied by ELISA with lectin or ligand. Structural changes of OVM after removing sialic acid were analyzed by circular dichroism and fluorescence spectroscopy. OVM could be binding to the hemagglutinin (HA) of avian influenza viruses HN and HN, this binding was specific and required the involvement of sialic acid. When sialic acid was removed, the binding was significantly reduced 71.5% and 64.35%, respectively. Therefore, sialic acid was proved as a recognition site which avian influenza virus bound to. Meanwhile, the endogenous fluorescence and surface hydrophobicity of OVM removing sialic acid were increased and the secondary structure tended to shift to random coil. This indicated that OVM molecules were in an unfolded state and spatial conformation disorder raising weakly. Remarkably, free sialic acid strongly promoted OVM binding to HA and thereby enhanced the interaction. It may contribute to the inhibition of host cell infection, agglutinate viruses. This study can be extended to the deepening of passive immunization field.

Authors : Xu Qi, Shan Yuanyuan, Wang Ning, Liu Yaping, Zhang Maojie, Ma Meihu,



(9) Zoonotic Influenza and Human Health-Part 2: Clinical Features, Diagnosis, Treatment, and Prevention Strategies.[TOP]

Pubmed ID :30069787
Publication Date : //
Zoonotic influenza viruses are those influenza viruses that cross the animal-human barrier and can cause disease in humans, manifesting from minor respiratory illnesses to multiorgan dysfunction. The increasing incidence of infections caused by these viruses worldwide has necessitated focused attention to improve both diagnostic as well as treatment modalities. In this second part of a two-part review, we discuss the clinical features, diagnostic modalities, and treatment of zoonotic influenza, and provide an overview of prevention strategies.

Authors : Mehta K, Goneau L W, Wong J, L'Huillier A G, Gubbay J B,



(10) Zoonotic Influenza and Human Health-Part 1: Virology and Epidemiology of Zoonotic Influenzas.[TOP]

Pubmed ID :30069735
Publication Date : //
Zoonotic influenza viruses are those that cross the animal-human barrier and can cause disease in humans, manifesting from minor respiratory illnesses to multiorgan dysfunction. They have also been implicated in the causation of deadly pandemics in recent history. The increasing incidence of infections caused by these viruses worldwide has necessitated focused attention to improve both diagnostic as well as treatment modalities. In this first part of a two-part review, we describe the structure of zoonotic influenza viruses, the relationship between mutation and pandemic capacity, pathogenesis of infection, and also discuss history and epidemiology.

Authors : Goneau L W, Mehta K, Wong J, L'Huillier A G, Gubbay J B,