A genome-wide CRISPR/Cas9 gene knockout screen identifies immunoglobulin superfamily DCC subclass member 4 as a key host factor that promotes influenza virus endocytosis

Influenza virus infection is dependent on host cellular factors, and identification of these factors and their underlying mechanisms can provide important information for the development of strategies to inhibit viral infection. Here, we used a highly pathogenic H5N1 influenza virus to perform a genome-wide CRISPR/Cas9 gene knockout screen in human lung epithelial cells (A549 cells), and found that knockout of transmembrane protein immunoglobulin superfamily DCC subclass member 4 (IGDCC4) significantly reduced the replication of the virus in A549 cells. Further studies showed that IGDCC4 interacted with the viral hemagglutinin protein and facilitated virus internalization into host cells. Animal infection studies showed that replication of H5N1 virus in the nasal turbinates, lungs, and kidneys of IGDCC4-knockout mice was significantly lower than that in the corresponding organs of wild-type mice. Half of the IGDCC4-knockout mice survived a lethal H5N1 virus challenge, whereas all of the wild-type mice died within 11 days of infection. Our study identifies a novel host factor that promotes influenza virus infection by facilitating internalization and provides insights that will support the development of antiviral therapies.

New Clade 2.3.4.4b H5N1 Highly Pathogenic Avian Influenza Genotype Detected in Europe in 2021

Despite their widespread distribution, the clade 2.3.4.4b H5N1 viruses have so far only been known in a single genotype variant in Europe. In the study presented, we report the first detection of a new highly pathogenic avian influenza H5N1 genotype in geese and ducks from a backyard farm in the Czech Republic. Phylogenetic analysis has revealed that the Czech H5N1 virus retained the A/Eurasian_Wigeon/Netherlands/1/2020-like backbone with an altered PB2 segment from co-circulating low pathogenic avian influenza viruses.

Graphical Method to Determine Sequence Variation on NA Protein of H5N1 Virus using Discrete Wavelet Transform

Influenza A virus belongs to the Orthomyxoviridae family and its genome is divided in eight distinct linear segments of negative-sense single stranded ribonucleic acid (RNA). Of all the eight influenza protein sequences, mutations in hemagglutinin and neuraminidase proteins show significant variations in their sequences. The threat of Influenza pandemic is ever rising due to its constant antigenic drift. Thus there is a need to characterize the genomic information in these viruses and signal processing methods offer the advantage of faster analysis in comparison to conventional techniques. Genomic information is converted into digital form by representation of the nucleotide bases in the form of mathematical sequences. In this paper, sequence variations of H5N1 virus have been studied using wavelet transforms as a signal analysis technique. Nucleotide sequences of neuraminidase protein of influenza virus occurring in different regions, in different hosts and over different years have been downloaded from National Centre for Biotechnology Information (NCBI) database. Sequences are aligned and converted into mathematical sequences then transformed using wavelet transforms. Graphical representations of the transformed sequences have been used to localise the regions of mutations along the sequence length.

H5Nx Viruses Emerged during the Suppression of H5N1 Virus Populations in Poultry

A major shift in the ecology of highly pathogenic avian influenza (HPAI) H5 viruses occurred from 2008 to 2014, when viruses with non-N1 neuraminidase genes (termed H5Nx viruses) emerged and caused global H5 virus outbreaks. Here, we demonstrate that nationwide control measures, including vaccination in China, successfully suppressed H5N1 populations in poultry, providing an opportunity for antigenically distinct H5Nx viruses to emerge.

Scrutinizing the Political and Economic Dynamics of China's Distribution of Vaccines in Securitizing Health

In the previous Pandemic of the H5N1 virus, the world is facing an uneven distribution of the vaccine. The irony is that developed countries get more access to vaccines compared to the country with more cases especially the global south countries. Today, the world is facing another pandemic which is The Covid-19 Pandemic. This virus vaccine has been found by Russia but has not yet gained international trust. According to experts, China is the country with the most potential to produce this vaccine. However, after the vaccine is successfully produced, there is no assurance that the vaccine will evenly be distributed as mandated by WHO. Based on these considerations, the researcher aimed to project the possibilities of vaccine distribution from China to global south countries. Researchers want to analyze the influence of a country's economic capacity and international politics on vaccine distribution, especially with China. To achieve this objective, we will compare the political and economic situation during the H5N1 pandemic and the political and economic situation during the Covid-19 pandemic. Countries used for comparison are Kenya, Yemen, the Philippines, and Indonesia. These four countries were chosen because it could represent different conditions of political and economic relations. The expected result is that we will get an overview of the distribution of the Covid-19 vaccine when China has started the distribution of the vaccine. We hope that this paper can be a consideration for developing countries' governments to be more sensitive and intense in carrying out vaccine diplomacy.

Study of Antibody-Dependent Reactions of Mast Cells In Vitro and in a Model of Severe Influenza Infection in Mice

We investigated the reaction of mouse peritoneal mast cells (MCs) in vitro after IgG-containing immune complex introduction using A/H5N1 and A/H1N1pdm09 influenza viruses as antigens. The sera of immune mice served as a source of IgG antibodies. The concentration of histamine in the supernatants was determined at 4 hours after incubation with antisera and virus. We compared the contribution of MCs to the pathogenesis of post-immunization influenza infection with A/H5N1 and A/H1N1 influenza viruses in mice. The mice were immunized parenterally with inactivated viruses and challenged with lethal doses of drift A/H5N1 and A/H1N1 influenza viruses on the 14th day after immunization. Simultaneously, half of the mice were injected intraperitoneally with a mixture of histamine receptor blockers (chloropyramine and quamatel). In in vitro experiments, the immune complex formed by A/H5N1 virus and antiserum caused a significant increase in the histamine release compared to immune serum or the virus alone. With regard to the A/H1N1 virus, such an increase was not significant. A/H1N1 immunization caused detectable HI response in mice at 12th day after immunization, in contrast to the A/H5N1 virus. After challenge of A/H5N1-immunized mice, administration of antihistamines increased the survival rate by up to 90%. When infecting the A/H1N1-immunized mice, 90% of the animals were already protected from lethal infection by day 14; the administration of histamine receptor blockers did not increase survival. Histological examination of the lungs has shown that toluidine blue staining allows to estimate the degree of MC degranulation. The possibility of in vitro activation of murine MCs by IgG-containing immune complexes has been shown. In a model of influenza infection, it was shown that the administration of histamine receptor blockers increased survival. When the protection was formed faster due to the earlier production of HI antibodies, the administration of histamine receptor blockers did not significantly affect the course of the infection. These data allow to propose that even if there are antibody-dependent MC reactions, they can be easily stopped by the administration of histamine receptor blockers.

Evaluation of Protective Efficacy of Influenza Virus Like Particles Prepared from H5N1 Virus of Clade 2.2.1.2 in Chickens

Highly pathogenic Avian Influenza (HPAI) viruses continue to cause severe economic losses in poultry species worldwide. HPAI virus of subtype H5N1 was reported in Egypt in 2006, and despite vaccination efforts, the virus has become endemic. The current study aims to evaluate the efficacy of a virus-like particle (VLP) based vaccine in vivo using specific pathogen-free (SPF) chickens. The vaccine was prepared from the HPAI H5N1 virus of clade 2.2.1.2 using the baculovirus expression system. The VLPs were quantitated and characterized, including electron microscopy. In addition, the protection level of the VLPs was evaluated by using two different regimens, including one dose and two-dose vaccinated groups, which gave up to 70% and 100% protection level, respectively. The results of this study emphasize the potential usefulness of the VLPs-based vaccine as an alternative vaccine candidate for the control of AIV infection in poultry.

Proteomics Analysis of Differential Expression of Lung Proteins In Response To Highly Pathogenic Avian Influenza Virus Infection In Chicken

Elucidation of molecular pathogenesis underlying virus-host interaction is important for the development of new diagnostic and therapeutic strategies against highly pathogenic avian influenza (HPAI) infection in chicken. However, chicken HPAI viral pathogenesis is not completely understood. To elucidate the intracellular signaling pathways and critical host proteins associated with influenza pathogenesis, we characterized the lung proteome of chicken infected with HPAI H5N1 virus (A/duck/India/02CA10/2011/Agartala). The chicken mass spectra data sets comprised1, 47, 451 MS scans and 19, 917 MS/MS scans. At local FDR 5% level, we identified total 3313 chicken proteins with presence of at least one unique peptide. At 12 hrs, 247 proteins are downregulated while 1754 proteins are downregulated at 48 hrs indicating that the host has succumbed to infection. There is expression of proteins of the predominant signaling pathways, such as TLR, RLR, NLR and JAK-STAT signaling. Activation of these pathways is associated with cytokine storm effect and thus may be the cause of severity of HPAI H5N1 infection in chicken. Further we identified proteins like MyD88, IKBKB, IRAK4, RELA, and MAVS involved in the critical signaling pathways and some other novel proteins (HNF4A, ELAVL1, FN1, COPS5, CUL1, BRCA1 and FYN) as main hub proteins that might play important roles in influenza pathogenesis in chicken. Taken together, we characterized the signaling pathways and the proteomic determinants responsible for disease pathogenesis in chicken infected with HPAI H5N1 virus.