Novel Avian Influenza A Virus Infections of Humans

Comparative evolution of influenza A virus H1 and H3 head and stalk domains across host species

IMPORTANCE

For decades, researchers have studied the rapid evolution of influenza A viruses for vaccine design and as a useful model system for the study of host/parasite evolution. By performing an exhaustive analysis of hemagglutinin protein (HA) sequences from 49 lineages independently evolving in birds, swine, canines, equines, and humans over the last century, our work uncovers surprising features of HA evolution. In particular, the canine H3 stalk, unlike human H3 and H1 stalk domains, is not evolving slowly, suggesting that evolution in the stalk domain is not universally constrained across all host species. Therefore, a broader multi-host perspective on HA evolution may be useful during the evaluation and design of stalk-targeted vaccine candidates.

Cross-species infection potential of avian influenza H13 viruses isolated from wild aquatic birds to poultry and mammals

Wild aquatic birds are the primary hosts of H13 avian influenza viruses (AIVs). Herein, we performed a genetic analysis of two H13 AIVs isolated from wild birds in China and evaluated their infection potential in poultry to further explore the potential for transmission from wild aquatic birds to poultry. Our results showed that the two strains belong to different groups, one strain (A/mallard/Dalian/DZ-137/2013; abbreviated as DZ137) belongs to Group I, whereas the other strain (A/Eurasian Curlew/Liaoning/ZH-385/2014; abbreviated as ZH385) belongs to Group III. In vitro experiments showed that both DZ137 and ZH385 can replicate efficiently in chicken embryo fibroblast cells. We found that these H13 AIVs can also efficiently replicate in mammalian cell lines, including human embryonic kidney cells and Madin-Darby canine kidney cells. In vivo experiments showed that DZ137 and ZH385 can infect 1-day-old specific pathogen-free (SPF) chickens, and that ZH385 has a higher replication ability in chickens than DZ137. Notably, only ZH385 can replicate efficiently in 10-day-old SPF chickens. However, neither DZ137 nor ZH385 can replicate well in turkeys and quails. Both DZ137 and ZH385 can replicate in 3-week-old mice. Serological surveillance of poultry showed a 4.6%-10.4% (15/328-34/328) antibody-positive rate against H13 AIVs in farm chickens. Our findings indicate that H13 AIVs have the replication ability in chickens and mice and may have a risk of crossing the host barrier from wild aquatic birds to poultry or mammals in the future.

Global distribution, receptor binding, and cross-species transmission of H6 influenza viruses: risks and implications for humans

The H6 subtype of avian influenza virus (AIV) is a pervasive subtype that is ubiquitously found in both wild bird and poultry populations across the globe. Recent investigations have unveiled its capacity to infect mammals, thereby expanding its host range beyond that of other subtypes and potentially facilitating its global transmission. This heightened breadth also endows H6 AIVs with the potential to serve as a genetic reservoir for the emergence of highly pathogenic avian influenza strains through genetic reassortment and adaptive mutations. Furthermore, alterations in key amino acid loci within the H6 AIV genome foster the evolution of viral infection mechanisms, which may enable the virus to surmount interspecies barriers and infect mammals, including humans, thus posing a potential threat to human well-being. In this review, we summarize the origins, dissemination patterns, geographical distribution, cross-species transmission dynamics, and genetic attributes of H6 influenza viruses. This study holds implications for the timely detection and surveillance of H6 AIVs.

Artesunate inhibits PDE4 leading to intracellular cAMP accumulation, reduced ERK/MAPK signaling, and blockade of influenza A virus vRNP nuclear export

Influenza A viruses (IAV) have been a major cause of mortality. Given the potential for future deadly pandemics, effective drugs are needed for the treatment of severe influenzas, such as those caused by H5N1 IAV. The anti-malaria drugs artemisinin and its derivates, including artesunate (AS), have been reported to have broad antiviral activities. Here, we showed AS's antiviral activity against H5N1, H1N1, H3N2 and oseltamivir-resistant influenza A(H1N1)virus in vitro. Moreover, we showed that AS treatment significantly protected mice from lethal challenges with H1N1 and H5N1 IAV. Strikingly, the combination of AS and peramivir treatment significantly improved survival outcomes compared to their monotherapy with either AS or peramivir. Furthermore, we demonstrated mechanistically that AS affected the later stages of IAV replication and limited nuclear export of viral ribonucleoprotein (vRNP) complexes. In A549 cells, we demonstrated for the first time that AS treatment induced cAMP accumulation via inhibiting PDE4, and consequently reduced ERK phosphorylation and blocked IAV vRNP export, and thus suppressed IAV replication. These AS's effects were reversed by the pre-treatment with a cAMP inhibitor SQ22536. Our findings suggest that AS could serve as a novel IAV inhibitor by interfering vRNP nuclear export to prevent and treat IAV infection.

Intensive poultry farming: A review of the impact on the environment and human health

Poultry farming is one of the most efficient animal husbandry methods and it provides nutritional security to a significant number of the world population. Using modern intensive farming techniques, global production has reached 133.4 mil. t in 2020, with a steady growth each year. Such intensive growth methods however lead to a significant environmental footprint. Waste materials such as poultry litter and manure can pose a serious threat to environmental and human health, and need to be managed properly. Poultry production and waste by-products are linked to NH₃, N₂O and CH₄ emissions, and have an impact on global greenhouse gas emissions, as well as animal and human health. Litter and manure can contain pesticide residues, microorganisms, pathogens, pharmaceuticals (antibiotics), hormones, metals, macronutrients (at improper ratios) and other pollutants which can lead to air, soil and water contamination as well as formation of antimicrobial/multidrug resistant strains of pathogens. Dust emitted from intensive poultry production operations contains feather and skin fragments, faeces, feed particles, microorganisms and other pollutants, which can adversely impact poultry health as well as the health of farm workers and nearby inhabitants. Fastidious odours are another problem that can have an adverse impact on health and quality of life of workers and surrounding population. This study discusses the current knowledge on the impact of intensive poultry farming on environmental and human health, as well as taking a look at solutions for a sustainable future.

Prevalence and risk factors for avian influenza virus (H5 and H9) contamination in peri-urban and rural live bird markets in Bangladesh

Avian influenza viruses (AIV) have been frequently detected in live bird markets (LBMs) around the world, primarily in urban areas, and have the ability to spillover to other species, including humans. Despite frequent detection of AIV in urban LBMs, the contamination of AIV on environmental surfaces in rural and peri-urban LBMs in Bangladesh is poorly documented. Therefore, we conducted this study to determine the prevalence of AIV subtypes within a subset of peri-urban and rural LBMs in Bangladesh and to further identify associated risk factors. Between 2017 and 2018, we collected faecal and offal samples from 200 stalls in 63 LBMs across four sub-districts. We tested the samples for the AIV matrix gene (M-gene) followed by H5, H7, and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We performed a descriptive analysis of market cleanliness and sanitation practices in order to further elucidate the relationship between LBM biosecurity and AIV subtypes by species, sample types, and landscape. Subsequently, we conducted a univariate analysis and a generalized linear mixed model (GLMM) to determine the risk factors associated with AIV contamination at individual stalls within LBMs. Our findings indicate that practices related to hygiene and the circulation of AIV significantly differed between rural and peri-urban live bird markets. 42.5% (95% CI: 35.56-49.67) of stalls were positive for AIV. A/H5, A/H9, and A HA/Untyped were detected in 10.5% (95% CI: 6.62-15.60), 9% (95% CI: 5.42-13.85), and 24.0% (95% CI: 18.26-30.53) of stalls respectively, with no detection of A/H7. Significantly higher levels of AIV were found in the Sonali chicken strain compared to the exotic broiler, and in offal samples compared to fecal samples. In the GLMM analysis, we identified several significant risk factors associated with AIV contamination in LBMs at the stall level. These include: landscape (AOR: 3.02; 95% CI: 1.18-7.72), the number of chicken breeds present (AOR: 2.4; 95% CI: 1.01-5.67), source of birds (AOR: 2.35; 95% CI: 1.0-5.53), separation of sick birds (AOR: 3.04; 95% CI: 1.34-6.92), disposal of waste/dead birds (AOR: 3.16; 95% CI: 1.41-7.05), cleaning agent (AOR: 5.99; 95% CI: 2.26-15.82), access of dogs (AOR: 2.52; 95% CI: 1.12-5.7), wild birds observed on site (AOR: 2.31; 95% CI: 1.01-5.3). The study further revealed a substantial prevalence of AIV with H5 and H9 subtypes in peri-urban and rural LBMs. The inadequate biosecurity measures at poultry stalls in Bangladesh increase the risk of AIV transmission from poultry to humans. To prevent the spread of AIV to humans and wild birds, we suggest implementing regular surveillance at live bird markets and enhancing biosecurity practices in peri-urban and rural areas in Bangladesh.

Characterization of Canine Influenza Virus A (H3N2) Circulating in Dogs in China from 2016 to 2018

Avian H3N2 influenza virus follows cross-host transmission and has spread among dogs in Asia since 2005. After 2015–2016, a new H3N2 subtype canine influenza epidemic occurred in dogs in North America and Asia. The disease prevalence was assessed by virological and serological surveillance in dogs in China. Herein, five H3N2 canine influenza virus (CIV) strains were isolated from 1185 Chinese canine respiratory disease samples in 2017–2018; these strains were on the evolutionary branch of the North American CIVs after 2016 and genetically far from the classical canine H3N2 strain discovered in China before 2016. Serological surveillance showed an HI antibody positive rate of 6.68%. H3N2 was prevalent in the coastal areas and northeastern regions of China. In 2018, it became the primary epidemic strain in the country. The QK01 strain of H3N2 showed high efficiency in transmission among dogs through respiratory droplets. Nevertheless, the virus only replicated in the upper respiratory tract and exhibited low pathogenicity in mice. Furthermore, highly efficient transmission by direct contact other than respiratory droplet transmission was found in a guinea pig model. The low-level replication in avian species other than ducks could not facilitate contact and airborne transmission in chickens. The current results indicated that a novel H3N2 virus has become a predominant epidemic strain in dogs in China since 2016 and acquired highly efficient transmissibility but could not be replicated in avian species. Thus, further monitoring is required for designing optimal immunoprophylactic tools for dogs and estimating the zoonotic risk of CIV in China.

Influenza

Seasonal influenza epidemics of variable severity pose challenges to public health. Annual vaccination is the primary way to prevent influenza, and a wide range of vaccines are available, including inactivated or live attenuated standard-dose, recombinant vaccines, as well as adjuvanted or high-dose vaccines for persons aged 65 years or older. Persons at increased risk for influenza complications include young children, persons with underlying medical conditions, and older adults. Prompt diagnosis of influenza can facilitate early initiation of antiviral treatment that provides the greatest clinical benefit. This article summarizes recommendations for providers on influenza vaccination, diagnostic testing, and antiviral treatment.

Natural Selection of H5N1 Avian Influenza A Viruses with Increased PA-X and NS1 Shutoff Activity

Influenza A viruses (IAV) can infect a broad range of mammalian and avian species. However, the host innate immune system provides defenses that restrict IAV replication and infection. Likewise, IAV have evolved to develop efficient mechanisms to counteract host antiviral responses to efficiently replicate in their hosts. The IAV PA-X and NS1 non-structural proteins are key virulence factors that modulate innate immune responses and virus pathogenicity during infection. To study the determinants of IAV pathogenicity and their functional co-evolution, we evaluated amino acid differences in the PA-X and NS1 proteins of early (1996–1997) and more recent (since 2016) H5N1 IAV. H5N1 IAV have zoonotic and pandemic potential and represent an important challenge both in poultry farming and human health. The results indicate that amino acid changes occurred over time, affecting the ability of these two non-structural H5N1 IAV proteins to inhibit gene expression and affecting virus pathogenicity. These results highlight the importance to monitor the evolution of these two virulence factors of IAV, which could result in enhanced viral replication and virulence.

Role of the Hemagglutinin Residue 227 in Immunogenicity of H5 and H7 Subtype Avian Influenza Vaccines in Chickens

Many H5 and H7 subtype avian influenza vaccines are poorly immunogenic in terms of inducing hemagglutination-inhibition (HI) antibody titers. Residue 227 (H3 numbering) in the receptor binding site in the hemagglutinin (HA) is critical for the detectability of HI antibodies induced by H5 influenza vaccines. However, whether the effect of residue 227 on immunogenicity can be generalized in different subtypes is unclear. In this study, the impact of HA residue 227 on immunogenicity of H5N1, H5N6, and H7N9 avian influenza vaccines was evaluated in chickens. Polymorphism analysis revealed that S227 is overwhelmingly dominant in HA of the H5N1 and H7N9 subtypes, whereas this amino acid is present in a small proportion of H5N6 viruses. The H5N1, H5N6, and H7N9 vaccines harboring S227 in HA induced relatively low HI titers at week 2 postimmunization (pi), and antibody titers increased at week 3 pi. S227N substitution in these vaccines consistently enhanced HI titers significantly. Another H5N6 vaccine harboring Q227 in HA elicited a robust HI antibody response, and Q227S substitution led to a significant drop of HI titers. Cross-HI testing against the wild-type and mutant viruses revealed that the amino acid at position 227 was associated with the detectability of HI titers induced by H5 and H7 avian influenza vaccines. The results indicate an important role of residue 227 in HA in immunogenicity of H5 and H7 subtype avian influenza vaccines in chickens. Our findings also provided useful information for vaccine seed virus selection and genetic engineering for immunogenicity enhancement of avian influenza vaccines.

Comprehensive Transcriptomic Analysis Identifies Novel Antiviral Factors Against Influenza A Virus Infection

Influenza A virus (IAV) has a higher genetic variation, leading to the poor efficiency of traditional vaccine and antiviral strategies targeting viral proteins. Therefore, developing broad-spectrum antiviral treatments is particularly important. Host responses to IAV infection provide a promising approach to identify antiviral factors involved in virus infection as potential molecular drug targets. In this study, in order to better illustrate the molecular mechanism of host responses to IAV and develop broad-spectrum antiviral drugs, we systematically analyzed mRNA expression profiles of host genes in a variety of human cells, including transformed and primary epithelial cells infected with different subtypes of IAV by mining 35 microarray datasets from the GEO database. The transcriptomic results showed that IAV infection resulted in the difference in expression of amounts of host genes in all cell types, especially those genes participating in immune defense and antiviral response. In addition, following the criteria of P<0.05 and |logFC|≥1.5, we found that some difference expression genes were overlapped in different cell types under IAV infection via integrative gene network analysis. IFI6, IFIT2, ISG15, HERC5, RSAD2, GBP1, IFIT3, IFITM1, LAMP3, USP18, and CXCL10 might act as key antiviral factors in alveolar basal epithelial cells against IAV infection, while BATF2, CXCL10, IFI44L, IL6, and OAS2 played important roles in airway epithelial cells in response to different subtypes of IAV infection. Additionally, we also revealed that some overlaps (BATF2, IFI44L, IFI44, HERC5, CXCL10, OAS2, IFIT3, USP18, OAS1, IFIT2) were commonly upregulated in human primary epithelial cells infected with high or low pathogenicity IAV. Moreover, there were similar defense responses activated by IAV infection, including the interferon-regulated signaling pathway in different phagocyte types, although the differentially expressed genes in different phagocyte types showed a great difference. Taken together, our findings will help better understand the fundamental patterns of molecular responses induced by highly or lowly pathogenic IAV, and the overlapped genes upregulated by IAV in different cell types may act as early detection markers or broad-spectrum antiviral targets.

Development of a monoclonal antibody-based antigen capture enzyme-linked immunosorbent assay for detection of H7N9 subtype avian influenza virus

To establish a rapid detection method for H7N9 avian influenza virus (AIV), monoclonal antibodies (mAbs) against hemagglutinin (HA) of H7N9 were developed to establish an antigen-capture enzyme-linked immunosorbent assay (AC-ELISA). AC-ELISA achieved high specificity and sensitivity, with a detection limit of 3.9 ng/mL for H7N9 HA protein (A/Zhejiang/DTID-ZJU01/2013), and 2-2 HA unit/100 μL for live H7N9 AIV. The inter- and intra-assay coefficient of variation was less than 10%. Compared with conventional virus isolation detection, the sensitivity and specificity were 94.96% and 88.24%, respectively. AC-ELISA proved to be a rapid and practical technique for the detection of H7N9 AIV.

Avian Influenza H7N9 Virus Adaptation to Human Hosts

Avian influenza virus A (H7N9), after circulating in avian hosts for decades, was identified as a human pathogen in 2013. Herein, amino acid substitutions possibly essential for human adaptation were identified by comparing the 4706 aligned overlapping nonamer position sequences (1–9, 2–10, etc.) of the reported 2014 and 2017 avian and human H7N9 datasets. The initial set of virus sequences (as of year 2014) exhibited a total of 109 avian-to-human (A2H) signature amino acid substitutions. Each represented the most prevalent substitution at a given avian virus nonamer position that was selectively adapted as the corresponding index (most prevalent sequence) of the human viruses. The majority of these avian substitutions were long-standing in the evolution of H7N9, and only 17 were first detected in 2013 as possibly essential for the initial human adaptation. Strikingly, continued evolution of the avian H7N9 virus has resulted in avian and human protein sequences that are almost identical. This rapid and continued adaptation of the avian H7N9 virus to the human host, with near identity of the avian and human viruses, is associated with increased human infection and a predicted greater risk of human-to-human transmission.

Protein transduction domain-mediated influenza NP subunit vaccine generates a potent immune response and protection against influenza virus in mice

The nucleoprotein (NP) is a highly conserved internal protein of the influenza virus, a major target for universal influenza vaccine. Our previous studies have proven NP-based subunit vaccine can provide partial protection in mice. It is reported that the protein transduction domain (PTD) TAT protein from human immunodeficiency virus-1 (HIV-1) is able to penetrate cells when added exogenous protein and could effectively enhance the immune response induced by the exogenous protein. In present study, the recombinant protein TAT-NP, a fusion of TAT and NP was effectively expressed in Escherichia coli and purified as a candidate component for an influenza vaccine. We evaluated the immunogenicity and protective efficacy of recombinant influenza TAT-NP vaccine by intranasal immunization. In vitro experiments showed that TAT-NP could efficiently penetrate into cells. Animal results showed that mice vaccinated with TAT-NP could not only induce higher levels of IgG and mucosal IgA, but also elicit a robust cellular immune response. Moreover, the TAT-NP fusion protein could significantly increase the protection of mice against lethal doses of homologous influenza virus PR8 and could also provide mice protection against a lethal dose challenge against heterosubtypic H9N2 and H3N2 influenza virus. In conclusion, the recombinant TAT-NP might be a universal vaccine candidate against influenza virus.

Contribution of Pro-Inflammatory Molecules Induced by Respiratory Virus Infections to Neurological Disorders

Neurobehavioral alterations and cognitive impairment are common phenomena that represent neuropsychiatric disorders and can be triggered by an exacerbated immune response against pathogens, brain injury, or autoimmune diseases. Pro-inflammatory molecules, such as cytokines and chemokines, are produced in the brain by resident cells, mainly by microglia and astrocytes. Brain infiltrating immune cells constitutes another source of these molecules, contributing to an impaired neurological synapse function, affecting typical neurobehavioral and cognitive performance. Currently, there is increasing evidence supporting the notion that behavioral alterations and cognitive impairment can be associated with respiratory viral infections, such as human respiratory syncytial virus, influenza, and SARS-COV-2, which are responsible for endemic, epidemic, or pandemic outbreak mainly in the winter season. This article will review the brain′s pro-inflammatory response due to infection by three highly contagious respiratory viruses that are the leading cause of acute respiratory illness, morbidity, and mobility in infants, immunocompromised and elderly population. How these respiratory viral pathogens induce increased secretion of pro-inflammatory molecules and their relationship with the alterations at a behavioral and cognitive level will be discussed.

Influenza vaccination: protecting the most vulnerable

Influenza virus infection causes seasonal epidemics and occasional pandemics, leading to huge morbidity and mortality worldwide. Vaccination against influenza is needed annually as protection from constantly mutating strains is required. Groups at high risk of poor outcomes include the elderly, the very young, pregnant women and those with chronic health conditions. However, vaccine effectiveness in the elderly is generally poor due to immunosenescence and may be altered due to “original antigenic sin”. Strategies to overcome these challenges in the elderly include high-dose or adjuvant vaccines. Other options include vaccinating healthcare workers and children as this reduces community-level influenza transmission. Current guidelines in the UK are that young children receive a live attenuated nasal spray vaccine, adults aged >65 years receive an adjuvanted trivalent inactivated vaccine and adults aged <65 years with comorbidities receive a quadrivalent inactivated vaccine. The goal of a universal influenza vaccine targeting conserved regions of the virus and avoiding the need for annual vaccination is edging closer with early-phase trials under way.

To protect the elderly from influenza, multiple strategies to overcome immunosenescence need to be utilised, such as improving vaccine efficacy, indirect protection via vaccinating children and healthcare workers, and developing a universal vaccinehttps://bit.ly/30KXzYn

Therapeutic p28 peptide targets essential H1N1 influenza virus proteins: insights from docking and molecular dynamics simulations

The H1N1 influenza virus causes a severe disease that affects the human respiratory tract leading to millions of deaths every year. At present, certain vaccines and few drugs are used to control the virus during seasonal outbreaks. However, high mutation rates and genetic reassortment make it challenging to prevent and mitigate outbreaks, leading to pandemics. Thus, alternate therapies are required for its management and control. Here, we report that a bacterial protein, azurin, and its peptide derivatives p18 and p28 target critical proteins of the influenza virus in an effective manner. The molecular docking studies show that the p28 peptide could target C-PB1, NS1-ED, PB2-CBD, PB2-RBD, NP, and PA proteins. These complexes were further subjected to the simulation of molecular dynamics and binding free energy calculations. The data indicate that p28 has an unusually high affinity and forms stable complexes with the viral proteins C-PB1, PB2-CBD, PB2-RBD, and NP. We suggest that the azurin derivative p28 peptide can act as an anti-influenza agent as it can bind to multiple targets and neutralize the virus. Additional experimental studies need to be conducted to evaluate its safety and efficacy as an anti-H1N1 molecule.

Assessment of serum ferritin as a biomarker in COVID-19: bystander or participant? Insights by comparison with other infectious and non-infectious diseases

BACKGROUND

The 2019 coronavirus disease (COVID-19) caused by the SARS-CoV-2 virus has an impact on all aspects of patient care. Serum ferritin generally represents a biomarker of choice when iron deficiency is suspected. However, ferritin is also an acute-phase-protein exhibiting elevated serum concentration in various inflammatory diseases. Here we focus on the role of serum ferritin for diagnostic and clinical management of patients with COVID-19 in comparison with other infectious and non-infectious diseases.

METHODS

We examined scientific articles listed in PubMed reporting on ferritin in various infectious and non-infectious diseases. We then compared these results with nine current COVID-19 ferritin reports published in 2020.

RESULTS

Several non-infectious, as well as non-COVID-19 infectious diseases, are characterised by a partly dramatic elevation of serum ferritin levels. All COVID-19 studies published between February and May 2020, which documented laboratory serum ferritin, indicate ferritin as a biomarker of COVID-19 severity in hospitalised patients.

CONCLUSIONS

Serum ferritin may be considered both a prognostic and stratifying biomarker that can also contribute to therapeutic decision-making concerning patients with COVID-19. It should be emphasised, however, that most scientific reports refer to cohorts in the Asian region. Further validation in other cohorts is urgently required.

Antiviral Activities of Compounds Isolated from Pinus densiflora (Pine Tree) against the Influenza A Virus

Pinus densiflora was screened in an ongoing project to discover anti-influenza candidates from natural products. An extensive phytochemical investigation provided 26 compounds, including two new megastigmane glycosides (1 and 2), 21 diterpenoids (3–23), and three flavonoids (24–26). The chemical structures were elucidated by a series of chemical reactions, including modified Mosher’s analysis and various spectroscopic measurements such as LC/MS and 1D- and 2D-NMR. The anti-influenza A activities of all isolates were screened by cytopathic effect (CPE) inhibition assays and neuraminidase (NA) inhibition assays. Ten candidates were selected, and detailed mechanistic studies were performed by various assays, such as Western blot, immunofluorescence, real-time PCR and flow cytometry. Compound 5 exerted its antiviral activity not by direct neutralizing virion surface proteins, such as HA, but by inhibiting the expression of viral mRNA. In contrast, compound 24 showed NA inhibitory activity in a noncompetitive manner with little effect on viral mRNA expression. Interestingly, both compounds 5 and 24 were shown to inhibit nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in a dose-dependent manner. Taken together, these results provide not only the chemical profiling of P. densiflora but also anti-influenza A candidates.

Yeast display platform technology to prepare oral vaccine against lethal H7N9 virus challenge in mice

Background

Existing methods for preparing influenza vaccines pose the greatest challenge against highly pandemic avian influenza H7N9 outbreak in the poultry and humans. Exploring a new strategy for manufacturing and delivering a safe and effective H7N9 vaccine is needed urgently.

Results

An alternative approach is to develop an influenza H7N9 oral vaccine based on yeast display technology in a timely manner. Hemagglutinin (HA) of A/Anhui/1/2013 (AH-H7N9) is used as a model antigen and characterized its expression on the surface of Saccharomyces cerevisiae (S.cerevisiae) EBY 100. Mice administrated orally with S.cerevisiae EBY100/pYD5-HA produced significant titers of IgG antibody as well as significant amounts of cytokines IFN-γ and IL-4. Importantly, S.cerevisiae EBY100/pYD5-HA could provide effective immune protection against homologous A/Anhui/1/2013 (AH-H7N9) virus challenge.

Conclusions

Our findings suggest that platform based on yeast surface technology provides an alternative approach to prepare a promising influenza H7N9 oral vaccine candidate that can significantly shorten the preparedness period and result in effective protection against influenza A pandemic.

Preparing for the 2019-2020 influenza season

Although the 2017-2018 influenza season had very high rates of influenza-associated illness, the 2018-2019 influenza season was comparable to previous seasons. Influenza A was the most commonly identified type worldwide, although variations in influenza A subtype prevalence existed. Influenza vaccination remains the single most effective way to prevent influenza-associated illness. A novel influenza antiviral, baloxavir, has demonstrated promising results; however, concerns about development of resistance exist.

From Influenza Virus to Novel Corona Virus (SARS-CoV-2)-The Contribution of Obesity

From the beginning of 2020, the governments and the health systems around the world are tackling infections and fatalities caused by the novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) resulting in the coronavirus disease 2019 (COVID-19). This virus pandemic has turned more complicated as individuals with co-morbidities like diabetes, cardiovascular conditions and obesity are at a high risk of acquiring infection and suffering from a more severe course of disease. Prolonged viral infection and obesity are independently known to lower the immune response and a combination can thus result in a "cytokine storm" and a substantial weakening of the immune system. With the rise in obesity cases globally, the chances that obese individuals will acquire infection and need hospitalization are heightened. In this review, we discuss why obesity, a low-grade chronic inflammation, contributes toward the increased severity in COVID-19 patients. We suggest that increased inflammation, activation of renin-angiotensin-aldosterone system, elevated adipokines and higher ectopic fat may be the factors contributing to the disease severity, in particular deteriorating the cardiovascular and lung function, in obese individuals. We look at the many lessons learnt from the 2009 H1N1 influenza A pandemic and relate it to the very little but fast incoming information that is available from the SARS-CoV-2 infected individuals with overweight and obesity.