Clinical and Immunological Characteristics of Human Infections With H5N6 Avian Influenza Virus

Synergistic effects of Lianhuaqingwen in combination with Oseltamivir and Baloxavir against seasonal influenza virus: In vitro and in vivo assessment

ETHNOPHARMACOLOGICAL RELEVANCE

Lianhuaqingwen (LH), a traditional Chinese medicine, presents a broad-spectrum antiviral effect and has been widely used to treat influenza. Given the potential rise of drug-resistant influenza viruses, it is necessary to develop new antiviral drugs and explore combination therapies involving LH in tandem with existing antivirals such as Oseltamivir acid (Osel) or Baloxavir (Bal). These multidrug combinations could help effectively control the seasonal influenza epidemics and reduce the disease burden.

AIM OF THE STUDY

This study aimed to evaluate the antiviral effects of LH, alone and in combination with Osel or Bal, against human seasonal influenza viruses in vitro and in vivo models.

MATERIALS AND METHODS

The antiviral efficacy of LH alone and LH in combination with Osel/Bal against seasonal influenza A viruses (IAVs) (H1N1 and H3N2 subtypes) and influenza B viruses (IBVs) (BV- and BY-lineages) was assessed in vitro using MDCK cells. The median effective concentration (EC50) was determined, and the drug synergies were analyzed. Additionally, the antiviral activity of LH monotherapy and LH + Osel/Bal combination therapy were evaluated in vivo using an H1N1-infected BABL/c mouse model by monitoring changes in body weight, survival rate, lung viral titer, pathological damage, and inflammatory reaction.

RESULTS

In vitro, LH alone and in combination with Osel/Bal exhibited antiviral activity against both IAVs and IBVs. The addition of LH to Osel/Bal improved the therapeutic efficacy compared to Osel/Bal alone. In vivo, LH monotherapy reduced body weight loss and increased the survival rates of H1N1-infected mice. LH in combination with Osel/Bal resulted in lower virus titers, more effective relief of pathological damage, and comparable low expression of inflammatory factors in the lungs of H1N1-infected mice compared to the use of Osel/Bal alone. Transcriptomic analysis of the lungs revealed that LH + Osel/Bal significantly increased the expression of genes associated with antiviral and anti-inflammatory effects.

CONCLUSIONS

This study evaluated the antiviral effects of LH monotherapy and combination therapy with Osel/Bal against human seasonal influenza viruses in vitro and in vivo models. The results suggest that combining LH with Osel or Bal could enhance the antiviral efficiency for influenza viruses compared to the monotherapy using any of these three drugs.

Risk distribution of human infections with avian influenza A (H5N1, H5N6, H9N2 and H7N9) viruses in China

Background

This study aimed to investigate epidemiologic characteristics of major human infection with avian influenza and explore the factors underlying the spatial distributions, particularly H5N6 and H9N2, as H9N2 could directly infect mankind and contribute partial or even whole internal genes to generate novel human-lethal reassortants such as H5N6. They pose potential threats to public health and agriculture.

Methods

This study collected cases of H5N1, H5N6, H9N2, and H7N9 in China, along with data on ecoclimatic, environmental, social and demographic factors at the provincial level. Boosted regression tree (BRT) models, a popular approach to ecological studies, has been commonly used for risk mapping of infectious diseases, therefore, it was used to investigate the association between these variables and the occurrence of human cases for each subtype, as well as to map the probabilities of human infections.

Results

A total of 1,123 H5N1, H5N6, H9N2, and H7N9 human cases have been collected in China from 2011 to 2024. Factors including density of pig and density of human population emerged as common significant predictors for H5N1 (relative contributions: 5.3, 5.8%), H5N6 (10.8, 6.4%), H9N2 (11.2, 7.3%), and H7N9 (9.4, 8.0%) infection. Overall, each virus has its own ecological and social drivers. The predicted distribution probabilities for H5N1, H5N6, H9N2, and H7N9 presence are highest in Guangxi, Sichuan, Guangdong, and Jiangsu, respectively, with values of 0.86, 0.96, 0.93 and 0.99.

Conclusion

This study highlighted the important role of social and demographic factors in the infection of different avian influenza, and suggested that monitoring and control of predicted high-risk areas should be prioritized.

A chimeric mRNA vaccine of S-RBD with HA conferring broad protection against influenza and COVID-19 variants

Influenza and coronavirus disease 2019 (COVID-19) represent two respiratory diseases that have significantly impacted global health, resulting in substantial disease burden and mortality. An optimal solution would be a combined vaccine capable of addressing both diseases, thereby obviating the need for multiple vaccinations. Previously, we conceived a chimeric protein subunit vaccine targeting both influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), utilizing the receptor binding domain of spike protein (S-RBD) and the stalk region of hemagglutinin protein (HA-stalk) components. By integrating the S-RBD from the SARS-CoV-2 Delta variant with the headless hemagglutinin (HA) from H1N1 influenza virus, we constructed stable trimeric structures that remain accessible to neutralizing antibodies. This vaccine has demonstrated its potential by conferring protection against a spectrum of strains in mouse models. In this study, we designed an mRNA vaccine candidate encoding the chimeric antigen. The resultant humoral and cellular immune responses were meticulously evaluated in mouse models. Furthermore, the protective efficacy of the vaccine was rigorously examined through challenges with either homologous or heterologous influenza viruses or SARS-CoV-2 strains. Our findings reveal that the mRNA vaccine exhibited robust immunogenicity, engendering high and sustained levels of neutralizing antibodies accompanied by robust and persistent cellular immunity. Notably, this vaccine effectively afforded complete protection to mice against H1N1 or heterosubtypic H5N8 subtypes, as well as the SARS-CoV-2 Delta and Omicron BA.2 variants. Additionally, our mRNA vaccine design can be easily adapted from Delta RBD to Omicron RBD antigens, providing protection against emerging variants. The development of two-in-one vaccine targeting both influenza and COVID-19, incorporating the mRNA platform, may provide a versatile approach to combating future pandemics.

A Chymotrypsin-Dependent Live-Attenuated Influenza Vaccine Provides Protective Immunity against Homologous and Heterologous Viruses

Influenza virus is one of the main pathogens causing respiratory diseases in humans. Vaccines are the most effective ways to prevent viral diseases. However, the limited protective efficacy of current influenza vaccines highlights the importance of novel, safe, and effective universal influenza vaccines. With the progress of the COVID-19 pandemic, live-attenuated vaccines delivered through respiratory mucosa have shown robustly protective efficacy. How to obtain a safe and effective live-attenuated vaccine has become a major challenge. Herein, using the influenza virus as a model, we have established a strategy to quickly obtain a live-attenuated vaccine by mutating the cleavage site of the influenza virus. This mutated influenza virus can be specifically cleaved by chymotrypsin. It has similar biological characteristics to the original strain in vitro, but the safety is improved by at least 100 times in mice. It can effectively protect against lethal doses of both homologous H1N1 and heterologous H5N1 viruses post mucosal administration, confirming that the vaccine generated by this strategy has good safety and broad-spectrum protective activities. Therefore, this study can provide valuable insights for the development of attenuated vaccines for respiratory viruses or other viruses with cleavage sites.

Exploring the global immune landscape of peripheral blood mononuclear cells in H5N6-infected patient with single-cell transcriptomics

BACKGROUND

Avian influenza viruses (AIV), particularly H5N6, have risen in infection frequency, prompting major concerns. Single-cell RNA sequencing (scRNA-seq) can illustrate the immune cell landscape present in the peripheral circulation of influenza H5N6-infected individuals at the single-cell level. This study attempted to employ scRNA-seq technology to map the potentially hidden single cell landscape of influenza H5N6.

METHODS

High-quality transcriptomes were generated from scRNA-seq data of peripheral blood mononuclear cells (PBMCs), which were taken from a critically-ill child diagnosed with H5N6 avian influenza infection and one healthy control donor. Cluster analysis was then performed on the scRNA-seq data to identify the different cell types. The pathways, pseudotime developmental trajectories and gene regulatory networks involved in different cell subpopulations were also explored.

RESULTS

In total, 3,248 single cell transcriptomes were captured by scRNA-seq from PBMC of the child infected with H5N6 avian influenza and the healthy control donor and further identified seven immune microenvironment cell types. In addition, a subsequent subpopulation analysis of innate lymphoid cells (ILC) and CD4+ T cells revealed that subpopulations of ILC and CD4+ T cells were involved in cytokine and inflammation-related pathways and had significant involvement in the biological processes of oxidative stress and cell death.

CONCLUSION

In conclusion, characterizing the overall immune cell composition of H5N6-infected individuals by assessing the immune cell landscape in the peripheral circulation of H5N6 avian influenza-infected and healthy control donors at single-cell resolution provides key information for understanding H5N6 pathogenesis.

SFTSV infection is associated with transient overproliferation of monoclonal lambda-type plasma cells

The impairment of antibody-mediated immunity is a major factor associated with fatal cases of severe fever with thrombocytopenia syndrome (SFTS). By collating the clinical diagnosis reports of 30 SFTS cases, we discovered the overproliferation of monoclonal plasma cells (MCP cells, CD38⁺cLambda⁺cKappa^-) in bone marrow, which has only been reported previously in multiple myeloma. The ratio of CD38⁺cLambda⁺ versus CD38⁺cKappa⁺ in SFTS cases with MCP cells was significantly higher than that in normal cases. MCP cells presented transient expression in the bone marrow, which was distinctly different from multiple myeloma. Moreover, the SFTS patients with MCP cells had higher clinical severity. Further, the overproliferation of MCP cells was also observed in SFTS virus (SFTSV)-infected mice with lethal infectious doses. Together, SFTSV infection induces transient overproliferation of monoclonal lambda-type plasma cells, which have important implications for the study of SFTSV pathogenesis, prognosis, and the rational development of therapeutics.

Structural basis for a human broadly neutralizing influenza A hemagglutinin stem-specific antibody including H17/18 subtypes

Influenza infection continues are a persistent threat to public health. The identification and characterization of human broadly neutralizing antibodies can facilitate the development of antibody drugs and the design of universal influenza vaccines. Here, we present structural information for the human antibody PN-SIA28's heterosubtypic binding of hemagglutinin (HA) from circulating and emerging potential influenza A viruses (IAVs). Aside from group 1 and 2 conventional IAV HAs, PN-SIA28 also inhibits membrane fusion mediated by bat-origin H17 and H18 HAs. Crystallographic analyses of Fab alone or in complex with H1, H14, and H18 HA proteins reveal that PN-SIA28 binds to a highly conserved epitope in the fusion domain of different HAs, with the same CDRHs but different CDRLs for different HAs tested, distinguishing it from other structurally characterized anti-stem antibodies. The binding characteristics of PN-SIA28 provides information to support the design of increasingly potent engineered antibodies, antiviral drugs, and/or universal influenza vaccines.

Significance of Preexisting Vector Immunity and Activation of Innate Responses for Adenoviral Vector-Based Therapy

An adenoviral (AdV)-based vector system is a promising platform for vaccine development and gene therapy applications. Administration of an AdV vector elicits robust innate immunity, leading to the development of humoral and cellular immune responses against the vector and the transgene antigen, if applicable. The use of high doses (10¹¹-10¹³ virus particles) of an AdV vector, especially for gene therapy applications, could lead to vector toxicity due to excessive levels of innate immune responses, vector interactions with blood factors, or high levels of vector transduction in the liver and spleen. Additionally, the high prevalence of AdV infections in humans or the first inoculation with the AdV vector result in the development of vector-specific immune responses, popularly known as preexisting vector immunity. It significantly reduces the vector efficiency following the use of an AdV vector that is prone to preexisting vector immunity. Several approaches have been developed to overcome this problem. The utilization of rare human AdV types or nonhuman AdVs is the primary strategy to evade preexisting vector immunity. The use of heterologous viral vectors, capsid modification, and vector encapsulation are alternative methods to evade vector immunity. The vectors can be optimized for clinical applications with comprehensive knowledge of AdV vector immunity, toxicity, and circumvention strategies.

Insight into the first multi-epitope-based peptide subunit vaccine against avian influenza A virus (H5N6): An immunoinformatics approach

The rampant spread of highly pathogenic avian influenza A (H5N6) virus has drawn additional concerns along with ongoing Covid-19 pandemic. Due to its migration-related diffusion, the situation is deteriorating. Without an existing effective therapy and vaccines, it will be baffling to take control measures. In this regard, we propose a revers vaccinology approach for prediction and design of a multi-epitope peptide based vaccine. The induction of humoral and cell-mediated immunity seems to be the paramount concern for a peptide vaccine candidate; thus, antigenic B and T cell epitopes were screened from the surface, membrane and envelope proteins of the avian influenza A (H5N6) virus, and passed through several immunological filters to determine the best possible one. Following that, the selected antigenic with immunogenic epitopes and adjuvant were linked to finalize the multi-epitope-based peptide vaccine by appropriate linkers. For the prediction of an effective binding, molecular docking was carried out between the vaccine and immunological receptors (TLR8). Strong binding affinity and good docking scores clarified the stringency of the vaccines. Furthermore, molecular dynamics simulation was performed within the highest binding affinity complex to observe the stability, and minimize the designed vaccine's high mobility region to order to increase its stability. Then, Codon optimization and other physicochemical properties were performed to reveal that the vaccine would be suitable for a higher expression at cloning level and satisfactory thermostability condition. In conclusion, predicting the overall in silico assessment, we anticipated that our designed vaccine would be a plausible prevention against avian influenza A (H5N6) virus.

Co-existence and co-infection of influenza A viruses and coronaviruses: Public health challenges

Since the 20th century, humans have lived through five pandemics caused by influenza A viruses (IAVs) (H1N1/1918, H2N2/1957, H3N2/1968, and H1N1/2009) and the coronavirus (CoV) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). IAVs and CoVs both have broad host ranges and share multiple hosts. Virus co-circulation and even co-infections facilitate genetic reassortment among IAVs and recombination among CoVs, further altering virus evolution dynamics and generating novel variants with increased cross-species transmission risk. Moreover, SARS-CoV-2 may maintain long-term circulation in humans as seasonal IAVs. Co-existence and co-infection of both viruses in humans could alter disease transmission patterns and aggravate disease burden. Herein, we demonstrate how virus-host ecology correlates with the co-existence and co-infection of IAVs and/or CoVs, further affecting virus evolution and disease dynamics and burden, calling for active virus surveillance and countermeasures for future public health challenges.

Progress towards the Development of a Universal Influenza Vaccine

Influenza viruses are responsible for millions of cases globally and significantly threaten public health. Since pandemic and zoonotic influenza viruses have emerged in the last 20 years and some of the viruses have resulted in high mortality in humans, a universal influenza vaccine is needed to provide comprehensive protection against a wide range of influenza viruses. Current seasonal influenza vaccines provide strain-specific protection and are less effective against mismatched strains. The rapid antigenic drift and shift in influenza viruses resulted in time-consuming surveillance and uncertainty in the vaccine protection efficacy. Most recent universal influenza vaccine studies target the conserved antigen domains of the viral surface glycoproteins and internal proteins to provide broader protection. Following the development of advanced vaccine technologies, several innovative strategies and vaccine platforms are being explored to generate robust cross-protective immunity. This review provides the latest progress in the development of universal influenza vaccines.

Monoclonal antibodies targeting the influenza virus N6 neuraminidase

Influenza A viruses are a diverse species that include 16 true hemagglutinin (HA) subtypes and 9 true neuraminidase (NA) subtypes. While the antigenicity of many HA subtypes is reasonably well studied, less is known about NA antigenicity, especially when it comes to non-human subtypes that only circulate in animal reservoirs. The N6 subtype NAs are mostly found in viruses infecting birds. However, they have also been identified in viruses that infect mammals, such as swine and seals. More recently, highly pathogenic H5N6 subtype viruses have caused rare infections and mortality in humans. Here, we generated murine mAbs to the N6 NA, characterized their breadth and antiviral properties in vitro and in vivo and mapped their epitopes by generating escape mutant viruses. We found that the antibodies had broad reactivity across the American and Eurasian N6 lineages, but relatively little binding to the H5N6 NA. Several of the antibodies exhibited strong NA inhibition activity and some also showed activity in the antibody dependent cellular cytotoxicity reporter assay and neutralization assay. In addition, we generated escape mutant viruses for six monoclonal antibodies and found mutations on the lateral ridge of the NA. Lastly, we observed variable protection in H4N6 mouse challenge models when the antibodies were given prophylactically.

N-linked glycosylation enhances hemagglutinin stability in avian H5N6 influenza virus to promote adaptation in mammals

Clade 2.3.4.4 avian H5Ny viruses, namely H5N2, H5N6, and H5N8, have exhibited unprecedented intercontinental spread in poultry. Among them, only H5N6 viruses are frequently reported to infect mammals and cause serious human infections. In this study, the genetic and biological characteristics of surface hemagglutinin (HA) from clade 2.3.4.4 H5Ny avian influenza viruses (AIVs) were examined for adaptation in mammalian infection. Phylogenetic analysis identified an amino acid (AA) deletion at position 131 of HA as a distinctive feature of H5N6 virus isolated from human patients. This single AA deletion was found to enhance H5N6 virus replication and pathogenicity in vitro and in mammalian hosts (mice and ferrets) through HA protein acid and thermal stabilization that resulted in reduced pH threshold from pH 5.7 to 5.5 for viral-endosomal membrane fusion. Mass spectrometry and crystal structure revealed that the AA deletion in HA at position 131 introduced an N-linked glycosylation site at 129, which increases compactness between HA monomers, thus stabilizes the trimeric structure. Our findings provide a molecular understanding of how HA protein stabilization promotes cross-species avian H5N6 virus infection to mammalian hosts.

Clinical characteristics and viral analysis of severe influenza A [H1N1]pdm09 in Guangzhou, 2019

OBJECTIVE

To understand the clinical characteristics of and analyze viral genes in patients with severe pneumonia due to [H1N1]pdm09 influenza virus in Guangzhou, 2019.

METHODS

The clinical data of 120 inpatients with laboratory-confirmed influenza A H1N1 virus from January to March 2019 were collected and analyzed. The subjects were diagnosed according to the criteria of the "Diagnosis and Treatment Program of Influenza A H1N1 (third Edition 2009)" issued by the Ministry of Health and were divided into severe and nonsevere groups. Serum samples during fever were collected for cytokine analysis, and the viral genes were analyzed after the virus cultured in MDCK cells. The data were analyzed by SPSS 16 software, and the results of gene sequencing were analyzed by MEGA 6 software.

RESULTS

Among the 120 inpatients, 36 (30%) were severe and 84 (70%) were nonsevere patients. The average age of severe patients was 53.11 ±19.94 years, the average age of nonsevere patients, at 44.03 ±24.47 years. There was no significant difference between the two groups (p< 0.05). There were significant differences in the rates of moist rales and dyspnea in critically ill patients (p< 0.05). There were significant differences in the white blood cell count (WBC), lactate dehydrogenase (LDH), creatine kinase (CK), serum creatinine (sCr), procalcitonin (PCT) and C-reactive protein (CRP) in severe patients with type A H1N1. Chest radiologic findings in severe patients showed ground glass shadows or pulmonary solid changes, and the difference was statistically significant for pulmonary fibrosis. Chronic lung disease (52.8%) and cardiovascular disease (27.8%) were independent risk factors for severe disease (p< 0.05). There were significant differences in secondary infections by Staphylococcus aureus (11.1%), pulmonary Aspergillus (22%) and Acinetobacter baumannii (16.7%) in critically ill patients (p< 0.05). Serum IL-8 in critically ill patients was significantly higher than those in nonsevere patients and healthy controls. The origin of virus strains in severe and nonsevere patients was the same, and there was no obvious mutation in the amino acid region of the antigenic site of the HA protein, but compared with the results of gene sequencing in previous years, the mutation sites showed a trend of annual accumulation. In conclusion, there was a high risk of severe pneumonia caused by H1N1 influenza A virus in Guangzhou in spring 2019. Long-term continuous surveillance, prevention and control of the virus should be carried out to predict its epidemiology and distribution. This article is protected by copyright. All rights reserved.

Emerging HxNy Influenza A Viruses

The continuous emergence and reemergence of diverse subtypes of influenza A viruses, which are known as "HxNy" and are mediated through the reassortment of viral genomes, account for seasonal epidemics, occasional pandemics, and zoonotic outbreaks. We summarize and discuss the characteristics of historic human pandemic HxNy viruses and diverse subtypes of HxNy among wild birds, mammals, and live poultry markets. In addition, we summarize the key molecular features of emerging infectious HxNy influenza viruses from the perspectives of the receptor binding of Hx, the inhibitor-binding specificities and drug-resistance features of Ny, and the matching of the gene segments. Our work enhances our understanding of the potential threats of novel reassortant influenza viruses to public health and provides recommendations for effective prevention, control, and research of this pathogen.

Selenium Deficiency Causes Inflammatory Injury in the Bursa of Fabricius of Broiler Chickens by Activating the Toll-like Receptor Signaling Pathway

The aim of our study was to observe the effect of selenium (Se) deficiency on inflammatory injury in the bursa of Fabricius of broiler chickens and to determine the role of the Toll-like receptor (TLR)/myeloid differential protein-88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway during this process. Here, we revealed that severe inflammatory injury occurred in the broiler bursa of Fabricius with Se deficiency via histopathology. Moreover, the ultrastructural pathological results showed that the nuclear, mitochondrial, endoplasmic reticulum and cytomembrane structures were damaged to varying degrees. Additionally, interleukin-2 (IL-2), interleukin-6 (IL-6), and interferon (IFN-γ) mRNA expression was markedly upregulated in the broiler bursa of Fabricius with Se deficiency. Furthermore, TLR, toll-interleukin-1 receptor domain-containing adapter-inducing interferon-β (TRIF), MyD88, and NF-κB mRNA expression was also markedly elevated in the broiler bursa of Fabricius with Se deficiency. The above results suggested that Se deficiency increases the expression of numerous proinflammatory cytokines and is probably due to the activation of the TLR/MyD88/NF-κB signaling pathway, which causes inflammatory injury in the bursa of Fabricius of broiler chickens. Our findings provide a theoretical reference for further studying the underlying mechanism of Se deficiency-induced inflammatory injury in the bursa of Fabricius of broiler chickens.

Duck-origin H5N6 avian influenza viruses induce different pathogenic and inflammatory effects in mice

Since 2013, H5N6 highly pathogenic avian influenza viruses have caused considerable economic losses in the poultry industry and have caused 24 laboratory-confirmed human cases. In this study, we isolated nine (B1-B9) H5N6 viruses from healthy ducks in Guangdong Province, Southern China from December 2018 to April 2019. Phylogenetic analysis revealed that B1, B2, B3, B4, B5, B7, B8, and B9 clustered into the G1.1 genotype and shared high sequence similarity with human H5N6 isolates from Southern China in 2017 and 2018. Meanwhile, B6 clustered into the G1.1.9 genotype. The hemagglutinin (HA), neuraminidase (NA) and nonstructural protein (NS) gene segments of B6 were closely related to the human H5N6 isolates, while the other genomic segments were closely related to H5N6 viruses isolated from waterfowl in Southern China. Compared to B7, B6 had higher pathogenicity and induced stronger inflammatory responses in mice. B6 carried a full-length PB1-F2 protein (90 aa), while the rest carried an 11-amino acid C-terminal-truncated PB1-F2. The PB1-F2 protein may increase the virulence of B6 compared to that of B7. Our findings provide insight into the pathogenic mechanisms of H5N6 viruses in mammals and emphasize the need for continued surveillance of circulating H5N6 viruses in ducks.

Risk Assessment for Highly Pathogenic Avian Influenza A(H5N6/H5N8) Clade 2.3.4.4 Viruses

The numerous global outbreaks and continuous reassortments of highly pathogenic avian influenza (HPAI) A(H5N6/H5N8) clade 2.3.4.4 viruses in birds pose a major risk to the public health. We investigated the tropism and innate host responses of 5 recent HPAI A(H5N6/H5N8) avian isolates of clades 2.3.4.4b, e, and h in human airway organoids and primary human alveolar epithelial cells. The HPAI A(H5N6/H5N8) avian isolates replicated productively but with lower competence than the influenza A(H1N1)pdm09, HPAI A(H5N1), and HPAI A(H5N6) isolates from humans in both or either models. They showed differential cellular tropism in human airway organoids; some infected all 4 major epithelial cell types: ciliated cells, club cells, goblet cells, and basal cells. Our results suggest zoonotic potential but low transmissibility of the HPAI A(H5N6/H5N8) avian isolates among humans. These viruses induced low levels of proinflammatory cytokines/chemokines, which are unlikely to contribute to the pathogenesis of severe disease.

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.

Genetic analysis and biological characteristics of novel clade 2.3.4.4 reassortment H5N6 avian influenza viruses from poultry in eastern China in 2016

OBJECTIVES

The continuous evolution of highly pathogenic H5N6 avian influenza viruses (AIVs) causes outbreaks in wildfowl and poultry, and occasional human infections. The aim of this study was to better understand the genetic relationships between these H5N6 AIVs from eastern China and other AIVs.

METHODS

In 2016, 1623 cloacal swabs were sampled from poultry in 18 LPMs in eastern China, and subsequently characterized systematically using gene sequencing, phylogenetic studies, and antigenic analysis. In addition, their pathogenicity in mammals was studied in BALB/c mice, which were inoculated with viruses, with survival rate and body weight recorded daily for 14 days.

RESULTS

In total, 56 H5N6 AIVs were isolated in eastern China and five representative isolates were selected for further study. In our study, the H5N6 AIVs clustered into clade 2.3.4.4, Group C, and their six internal segments were derived from H6N6 and H9N2 viruses, or both, suggesting extensive reassortant among H5N6 AIVs with other subtypes. These H5N6 viruses could replicate in the lungs without prior adaptation, and exhibited slight-to-moderate virulence in mice.

CONCLUSIONS

The continuous circulation of these novel H5N6 viruses suggests the importance of persistent surveillance of H5N6 AIVs in poultry.

Complement Decay-Accelerating Factor is a modulator of influenza A virus lung immunopathology

Clearance of viral infections, such as SARS-CoV-2 and influenza A virus (IAV), must be fine-tuned to eliminate the pathogen without causing immunopathology. As such, an aggressive initial innate immune response favors the host in contrast to a detrimental prolonged inflammation. The complement pathway bridges innate and adaptive immune system and contributes to the response by directly clearing pathogens or infected cells, as well as recruiting proinflammatory immune cells and regulating inflammation. However, the impact of modulating complement activation in viral infections is still unclear. In this work, we targeted the complement decay-accelerating factor (DAF/CD55), a surface protein that protects cells from non-specific complement attack, and analyzed its role in IAV infections. We found that DAF modulates IAV infection in vivo, via an interplay with the antigenic viral proteins hemagglutinin (HA) and neuraminidase (NA), in a strain specific manner. Our results reveal that, contrary to what could be expected, DAF potentiates complement activation, increasing the recruitment of neutrophils, monocytes and T cells. We also show that viral NA acts on the heavily sialylated DAF and propose that the NA-dependent DAF removal of sialic acids exacerbates complement activation, leading to lung immunopathology. Remarkably, this mechanism has no impact on viral loads, but rather on the host resilience to infection, and may have direct implications in zoonotic influenza transmissions.

Exacerbated complement activation and immune deregulation are at the basis of several pathologies induced by respiratory viruses. Here, we report that complement decay-accelerating factor (DAF), which inhibits complement activation in healthy cells, increases disease severity upon influenza A virus (IAV) infection. Remarkably, DAF interaction with IAV proteins, hemagglutinin (HA) and neuraminidase (NA), resulted in excessive complement activation and recruitment of innate and adaptive immune cells, without affecting viral loads. Furthermore, we observed that viral NA directly cleaves DAF and promotes complement activation, providing a possible link between IAV-DAF interaction and pathology. Therefore, our results unveil a novel pathway that could modulate disease severity, which may help to understand the increased pathogenicity of zoonotic and pandemic IAV infections.

Development of an antigen-ELISA and a colloidal gold-based immunochromatographic strip based on monoclonal antibodies for detection of avian influenza A(H5) viruses

Avian influenza A(H5) viruses (avian IAVs) pose a major threat to the economy and public health. We developed an antigen-ELISA (ag-ELISA) and a colloidal gold-based immunochromatographic strip for the rapid detection of avian A(H5) viruses. Both detection methods displayed no cross-reactivity with other viruses (e.g., other avian IAVs, infectious bursal disease virus, Newcastle disease virus, infectious bronchitis virus, avian paramyxovirus). The ag-ELISA was sensitive down to 0.5 hemagglutinin (HA) units/100 µL of avian A(H5) viruses and 7.5 ng/mL of purified H5 HA proteins. The immunochromatographic strip was sensitive down to 1 HA unit/100 µL of avian A(H5) viruses. Both detection methods exhibited good reproducibility with CVs < 10%. For 200 random poultry samples, the sensitivity and specificity of the ag-ELISA were 92.6% and 98.8%, respectively, and for test strips were 88.9% and 98.3%, respectively. Both detection methods displayed high specificity, sensitivity, and stability, making them suitable for rapid detection and field investigation of avian A(H5) viruses.

Cytokine/Chemokine Expression Is Closely Associated Disease Severity of Human Adenovirus Infections in Immunocompetent Adults and Predicts Disease Progression

Increasing human Adenovirus (HAdV) infections complicated with acute respiratory distress syndrome (ARDS) even fatal outcome were reported in immunocompetent adolescent and adult patients. Here, we characterized the cytokine/chemokine expression profiles of immunocompetent patients complicated with ARDS during HAdV infection and identified biomarkers for disease severity/progression. Forty-eight cytokines/chemokines in the plasma samples from 19 HAdV-infected immunocompetent adolescent and adult patients (ten complicated with ARDS) were measured and analyzed in combination with clinical indices. Immunocompetent patients with ARDS caused by severe acute respiratory disease coronavirus (SARS-CoV)-2, 2009 pandemic H1N1 (panH1N1) or bacteria were included for comparative analyses. Similar indices of disease course/progression were found in immunocompetent patients with ARDS caused by HAdV, SARS-CoV-2 or panH1N infections, whereas the HAdV-infected group showed a higher prevalence of viremia, as well as increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and creatine kinase (CK). Expression levels of 33 cytokines/chemokines were increased significantly in HAdV-infected patients with ARDS compared with that in healthy controls, and many of them were also significantly higher than those in SARS-CoV-2-infected and panH1N1-infected patients. Expression of interferon (IFN)-γ, interleukin (IL)-1β, hepatocyte growth factor (HGF), monokine induced by IFN-γ (MIG), IL-6, macrophage-colony stimulating factor (M-CSF), IL-10, IL-1α and IL-2Ra was significantly higher in HAdV-infected patients with ARDS than that in those without ARDS, and negatively associated with the ratio of the partial pressure of oxygen in arterial blood/fraction of inspired oxygen (PaO₂/FiO₂). Analyses of the receiver operating characteristic curve (ROC) showed that expression of IL-10, M-CSF, MIG, HGF, IL-1β, IFN-γ and IL-2Ra could predict the progression of HAdV infection, with the highest area under the curve (AUC) of 0.944 obtained for IL-10. Of note, the AUC value for the combination of IL-10, IFN-γ, and M-CSF reached 1. In conclusion, the “cytokine storm” occurred during HAdV infection in immunocompetent patients, and expression of IL-10, M-CSF, MIG, HGF, IL-1β, IFN-γ and IL-2Ra was closely associated with disease severity and could predict disease progression.

Rapid humoral immune responses are required for recovery from haemorrhagic fever with renal syndrome patients

Haemorrhagic fever with renal syndrome (HFRS) following Hantaan virus (HTNV) infection displays variable clinical signs. Humoral responses elicited during HTNV infections are considered important, however, this process remains poorly understood. Herein, we have investigated the phenotype, temporal dynamics, and characteristics of B-cell receptor (BCR) repertoire in an HFRS cohort. The serological profiles were characterized by a lowered expression level of nucleoprotein (NP)-specific antibody in severe cases. Importantly, B-cell subsets were activated and proliferated within the first two weeks of symptom onset and moderate cases reacted more rapidly. BCR analysis in the recovery phase revealed a dramatic increase in the immunoglobulin gene diversity which was more significantly progressed in moderate infections. In severe cases, B-cell-related transcription was lower with inflammatory sets overactivated. Taken together, these data suggest the clinical signs and disease recovery in HFRS patients were positively impacted by rapid and efficacious humoral responses.

Genetic characterization of an H5N6 avian influenza virus with multiple origins from a chicken in southern China, October 2019

BACKGROUND

Highly pathogenic avian influenza viruses (HPAIVs) of H5 subtype pose a great threat to the poultry industry and human health. In recent years, H5N6 subtype has rapidly replaced H5N1 as the most predominate HPAIV subtype circulating in domestic poultry in China. In this study, we describe the genetic and phylogenetic characteristics of a prevalent H5N6 strain in Guangdong, China.

RESULTS

Nucleotide sequencing identified a H5N6 subtype HPAIV, designated as A/chicken/Dongguan/1101/2019 (DG/19), with a multibasic cleavage site in the hemagglutinin (HA). Phylogenetic analysis revealed DG/19 was a reassortant of H5N1, H5N2, H5N8, and H6N6 subtypes of avian influenza viruses. A number of mammalian adaptive markers such as D36N in the HA were identified.

CONCLUSIONS

Our results showed that HPAIV H5N6 strains still emerge in well-managed groups of chicken farms. Considering the increasing prevalence of H5N6 HPAIV, and the fact that H5N6 HPAIVs are well adapted to migratory birds, an enhanced surveillance for the East Asian-Australasian flyway should be undertaken to prevent potential threats to the poultry industry and human health.

Avian influenza A (H7N9) virus: from low pathogenic to highly pathogenic

The avian influenza A (H7N9) virus is a zoonotic virus that is closely associated with live poultry markets. It has caused infections in humans in China since 2013. Five waves of the H7N9 influenza epidemic occurred in China between March 2013 and September 2017. H7N9 with low-pathogenicity dominated in the first four waves, whereas highly pathogenic H7N9 influenza emerged in poultry and spread to humans during the fifth wave, causing wide concern. Specialists and officials from China and other countries responded quickly, controlled the epidemic well thus far, and characterized the virus by using new technologies and surveillance tools that were made possible by their preparedness efforts. Here, we review the characteristics of the H7N9 viruses that were identified while controlling the spread of the disease. It was summarized and discussed from the perspectives of molecular epidemiology, clinical features, virulence and pathogenesis, receptor binding, T-cell responses, monoclonal antibody development, vaccine development, and disease burden. These data provide tools for minimizing the future threat of H7N9 and other emerging and re-emerging viruses, such as SARS-CoV-2.

Pathogenic assessment of avian influenza viruses in migratory birds

Several subtypes of avian influenza (AI) viruses have caused human infections in recent years; however, there is a severe knowledge gap regarding the capacity of wild bird viruses to infect mammals. To assess the risk of mammalian infection by AI viruses from their natural reservoirs, a panel of isolates from 34 wild birds was examined in animal models. All selected AI virus subtypes were found to predominantly possess Eurasian lineage, although reassortment with North American lineage AI viruses was also noted in some isolates. When used to infect chickens, 20 AI isolates could be recovered from oropharyngeal swabs at 5 days post-infection (dpi) without causing significant morbidity. Similarly, mild to no observable disease was observed in mice infected with these viruses although the majority replicated efficiently in murine lungs. As expected, wild bird AI isolates were found to recognize avian-like receptors, while a few strains also exhibited detectable human-like receptor binding. Selected strains were further tested in ferrets, and 15 out of 20 were found to shed the virus in the upper respiratory tract until 5 dpi. Overall, we demonstrate that a diversity of low-pathogenic AI viruses carried by wild migratory birds have the capacity to infect land-based poultry and mammalian hosts while causing minimal signs of clinical disease. This study reiterates that there is a significant capacity for interspecies transmission of AI viruses harboured by wild aquatic birds. Thus, these viruses pose a significant threat to human health underscoring the need for continued surveillance.

N-linked glycosylation at site 158 of the HA protein of H5N6 highly pathogenic avian influenza virus is important for viral biological properties and host immune responses

Since 2014, clade 2.3.4.4 has become the dominant epidemic branch of the Asian lineage H5 subtype highly pathogenic avian influenza virus (HPAIV) in southern and eastern China, while the H5N6 subtype is the most prevalent. We have shown earlier that lack of glycosylation at position 158 of the hemagglutinin (HA) glycoprotein due to the T160A mutation is a key determinant of the dual receptor binding property of clade 2.3.4.4 H5NX subtypes. Our present study aims to explore other effects of this site among H5N6 viruses. Here we report that N-linked glycosylation at site 158 facilitated the assembly of virus-like particles and enhanced virus replication in A549, MDCK, and chicken embryonic fibroblast (CEF) cells. Consistently, the HA-glycosylated H5N6 virus induced higher levels of inflammatory factors and resulted in stronger pathogenicity in mice than the virus without glycosylation at site 158. However, H5N6 viruses without glycosylation at site 158 were more resistant to heat and bound host cells better than the HA-glycosylated viruses. H5N6 virus without glycosylation at this site triggered the host immune response mechanism to antagonize the viral infection, making viral pathogenicity milder and favoring virus spread. These findings highlight the importance of glycosylation at site 158 of HA for the pathogenicity of the H5N6 viruses.

The preliminary comparative results between Covid-19 and non-Covid-19 patients in Western China

BACKGROUND

This study aims to investigate the comparative clinical characteristics of Covid-19 and non-Covid-19 patients.

METHODS

Fifteen Covid-19 and 93 non-Covid-19 patients were included in RNA testing. All epidemiological and clinical data were collected and analyzed, and then comparative results were carried out.

RESULTS

Covid-19 patients were older (46.40 ± 18.21 years vs 34.43 ± 18.80 years) and had a higher body weight (70.27 ± 10.67 kg vs 60.54 ± 12.33 kg, P < 0.05). The main symptoms that were similar between Covid-19 and non-Covid-19 patients, and Covid-19 patients showed a lower incidence of sputum production (6.67% vs 45.16%, P < 0.01) and a lower white-cell count (4.83 × 10⁹/L vs 7.43 × 10⁹/L) and lymphocyte count (0.90 × 10⁹/L vs 1.57 × 10⁹/L, P < 0.01). Although there were no differences, C-reactive protein and interleukin-6 were elevated in Covid-19 patients. The sensitivity and negative predictive value of CT images were 0.87 and 0.97, respectively. Covid-19 patients showed a higher contact history of Wuhan residents (80% vs 30.11%) and higher familial clustering (53.33% vs 8.60%, P < 0.001). Covid-19 patients showed a higher major adverse events (ARDS, 13.33%; death, 6.67%; P < 0.05).

CONCLUSION

Our results suggested that Covid-19patients had a significant history of exposure and familial clustering and a higher rate of severe status; biochemical indicators showed lymphocyte depletion.

Laboratory Diagnosis and Monitoring the Viral Shedding of SARS-CoV-2 Infection

The worldwide epidemic of coronavirus disease 2019 (COVID-19) is ongoing. Rapid and accurate detection of the causative virus SARS-CoV-2 is vital for the treatment and control of COVID-19. In this study, the comparative sensitivity of different respiratory specimen types were retrospectively analyzed using 3,552 clinical samples from 410 COVID-19 patients confirmed by Guangdong CDC (Center for Disease Control and Prevention). Except for bronchoalveolar lavage fluid (BALF), the sputum possessed the highest positive rate (73.4%-87.5%), followed by nasal swabs (53.1%-85.3%) for both severe and mild cases during the first 14 days after illness onset (d.a.o.). Viral RNA could be detected in all BALF samples collected from the severe group within 14 d.a.o. and lasted up to 46 d.a.o. Moreover, although viral RNA was negative in the upper respiratory samples, it was also positive in BALF samples in most cases from the severe group during treatment. Notably, no viral RNA was detected in BALF samples from the mild group. Despite typical ground-glass opacity observed via computed tomographic scans, no viral RNA was detected in the first three or all upper respiratory tract specimens from some COVID-19 patients. In conclusion, sputum is most sensitive for routine laboratory diagnosis of COVID-19, followed by nasal swabs. Detection of viral RNA in BALF improves diagnostic accuracy in severe COVID-19 patients.

Dominant subtype switch in avian influenza viruses during 2016-2019 in China

We have surveyed avian influenza virus (AIV) genomes from live poultry markets within China since 2014. Here we present a total of 16,091 samples that were collected from May 2016 to February 2019 in 23 provinces and municipalities in China. We identify 2048 AIV-positive samples and perform next generation sequencing. AIV-positive rates (12.73%) from samples had decreased substantially since 2016, compared to that during 2014-2016 (26.90%). Additionally, H9N2 has replaced H5N6 and H7N9 as the dominant AIV subtype in both chickens and ducks. Notably, novel reassortants and variants continually emerged and disseminated in avian populations, including H7N3, H9N9, H9N6 and H5N6 variants. Importantly, almost all of the H9 AIVs and many H7N9 and H6N2 strains prefer human-type receptors, posing an increased risk for human infections. In summary, our nation-wide surveillance highlights substantial changes in the circulation of AIVs since 2016, which greatly impacts the prevention and control of AIVs in China and worldwide.

Laboratory Diagnosis and Monitoring the Viral Shedding of SARS-CoV-2 Infection

The worldwide epidemic of coronavirus disease 2019 (COVID-19) is ongoing. Rapid and accurate detection of the causative virus SARS-CoV-2 is vital for the treatment and control of COVID-19. In this study, the comparative sensitivity of different respiratory specimen types were retrospectively analyzed using 3,552 clinical samples from 410 COVID-19 patients confirmed by Guangdong CDC (Center for Disease Control and Prevention). Except for bronchoalveolar lavage fluid (BALF), the sputum possessed the highest positive rate (73.4%-87.5%), followed by nasal swabs (53.1%-85.3%) for both severe and mild cases during the first 14 days after illness onset (d.a.o.). Viral RNA could be detected in all BALF samples collected from the severe group within 14 d.a.o. and lasted up to 46 d.a.o. Moreover, although viral RNA was negative in the upper respiratory samples, it was also positive in BALF samples in most cases from the severe group during treatment. Notably, no viral RNA was detected in BALF samples from the mild group. Despite typical ground-glass opacity observed via computed tomographic scans, no viral RNA was detected in the first three or all upper respiratory tract specimens from some COVID-19 patients. In conclusion, sputum is most sensitive for routine laboratory diagnosis of COVID-19, followed by nasal swabs. Detection of viral RNA in BALF improves diagnostic accuracy in severe COVID-19 patients.

Dynamic PB2-E627K substitution of influenza H7N9 virus indicates the in vivo genetic tuning and rapid host adaptation

Avian-origin influenza viruses overcome the bottleneck of the interspecies barrier and infect humans through the evolution of variants toward more efficient replication in mammals. The dynamic adaptation of the genetic substitutions and the correlation with the virulence of avian-origin influenza virus in patients remain largely elusive. Here, based on the one-health approach, we retrieved the original virus-positive samples from patients with H7N9 and their surrounding poultry/environment. The specimens were directly deep sequenced, and the subsequent big data were integrated with the clinical manifestations. Unlike poultry/environment-derived samples with the consistent dominance of avian signature 627E of H7N9 polymerase basic protein 2 (PB2), patient specimens had diverse ratios of mammalian signature 627K, indicating the rapid dynamics of H7N9 adaptation in patients during the infection process. In contrast, both human- and poultry/environment-related viruses had constant dominance of avian signature PB2-701D. The intrahost dynamic adaptation was confirmed by the gradual replacement of 627E by 627K in H7N9 in the longitudinally collected specimens from one patient. These results suggest that host adaptation for better virus replication to new hosts, termed "genetic tuning," actually occurred in H7N9-infected patients in vivo. Notably, our findings also demonstrate the correlation between rapid host adaptation of H7N9 PB2-E627K and the fatal outcome and disease severity in humans. The feature of H7N9 genetic tuning in vivo and its correlation with the disease severity emphasize the importance of testing for the evolution of this avian-origin virus during the course of infection.

Antigenic Variation of Avian Influenza A(H5N6) Viruses, Guangdong Province, China, 2014-2018

Market surveillance showed continuing circulation of avian influenza A(H5N6) virus in live poultry markets in Guangdong Province in 2017, despite compulsory vaccination for avian influenza A(H5Nx) and A(H7N9). We analyzed H5N6 viruses from 2014-2018 from Guangdong Province, revealing antigenic drift and decreased antibody response against the vaccine strain in vaccinated chickens.

Plasma IP-10 and MCP-3 levels are highly associated with disease severity and predict the progression of COVID-19

BACKGROUND

The outbreak of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 was first reported in Wuhan, December 2019, and continuously poses a serious threat to public health, highlighting the urgent need of identifying biomarkers for disease severity and progression.

OBJECTIVE

We sought to identify biomarkers for disease severity and progression of COVID-19.

METHODS

Forty-eight cytokines in the plasma samples from 50 COVID-19 cases including 11 critically ill, 25 severe, and 14 moderate patients were measured and analyzed in combination with clinical data.

RESULTS

Levels of 14 cytokines were found to be significantly elevated in COVID-19 cases and showed different expression profiles in patients with different disease severity. Moreover, expression levels of IFN-γ-induced protein 10, monocyte chemotactic protein-3, hepatocyte growth factor, monokine-induced gamma IFN, and macrophage inflammatory protein 1 alpha, which were shown to be highly associated with disease severity during disease progression, were remarkably higher in critically ill patients, followed by severe and then the moderate patients. Serial detection of the 5 cytokines in 16 cases showed that continuously high levels were associated with deteriorated progression of disease and fatal outcome. Furthermore, IFN-γ-induced protein 10 and monocyte chemotactic protein-3 were excellent predictors for the progression of COVID-19, and the combination of the 2 cytokines showed the biggest area under the curve of the receiver-operating characteristics calculations with a value of 0.99.

CONCLUSIONS

In this study, we report biomarkers that are highly associated with disease severity and progression of COVID-19. These findings add to our understanding of the immunopathologic mechanisms of severe acute respiratory syndrome coronavirus 2 infection, and provide potential therapeutic targets and strategies.

Efficacy of Neuraminidase Inhibitors against H5N6 Highly Pathogenic Avian Influenza Virus in a Nonhuman Primate Model

Attention has been paid to H5N6 highly pathogenic avian influenza virus (HPAIV) because of its heavy burden on the poultry industry and human mortality. Since an influenza A virus carrying N6 neuraminidase (NA) has never spread in humans, the potential for H5N6 HPAIV to cause disease in humans and the efficacy of antiviral drugs against the virus need to be urgently assessed. We used nonhuman primates to elucidate the pathogenesis of H5N6 HPAIV as well as to determine the efficacy of antiviral drugs against the virus. H5N6 HPAIV infection led to high fever in cynomolgus macaques. The lung injury caused by the virus was severe, with diffuse alveolar damage and neutrophil infiltration. In addition, an increase in interferon alpha (IFN-α) showed an inverse correlation with virus titers during the infection process. Oseltamivir was effective for reducing H5N6 HPAIV propagation, and continuous treatment with peramivir reduced virus propagation and the severity of symptoms in the early stage. This study also showed pathologically severe lung injury states in cynomolgus macaques infected with H5N6 HPAIV, even in those that received early antiviral drug treatments, indicating the need for close monitoring and further studies on virus pathogenicity and new antiviral therapies.

Elevated plasma levels of selective cytokines in COVID-19 patients reflect viral load and lung injury

A recent outbreak of pneumonia in Wuhan, China was found to be caused by a 2019 novel coronavirus (2019-nCoV or SARS-CoV-2 or HCoV-19). We previously reported the clinical features of 12 patients with 2019-nCoV infections in Shenzhen, China. To further understand the pathogenesis of COVID-19 and find better ways to monitor and treat the disease caused by 2019-nCoV, we measured the levels of 48 cytokines in the blood plasma of those 12 COVID-19 patients. Thirty-eight out of the 48 measured cytokines in the plasma of 2019-nCoV-infected patients were significantly elevated compared to healthy individuals. Seventeen cytokines were linked to 2019-nCoV loads. Fifteen cytokines, namely M-CSF, IL-10, IFN-α2, IL-17, IL-4, IP-10, IL-7, IL-1ra, G-CSF, IL-12, IFN-γ, IL-1α, IL-2, HGF and PDGF-BB, were strongly associated with the lung-injury Murray score and could be used to predict the disease severity of 2019-nCoV infections by calculating the area under the curve of the receiver-operating characteristics. Our results suggest that 2019-nCoV infections trigger extensive changes in a wide array of cytokines, some of which could be potential biomarkers of disease severity of 2019-nCoV infections. These findings will likely improve our understanding of the immunopathologic mechanisms of this emerging disease. Our results also suggest that modulators of cytokine responses may play a therapeutic role in combating the disease once the functions of these elevated cytokines have been characterized.

Clinical and biochemical indexes from 2019-nCoV infected patients linked to viral loads and lung injury

The outbreak of the 2019-nCoV infection began in December 2019 in Wuhan, Hubei province, and rapidly spread to many provinces in China as well as other countries. Here we report the epidemiological, clinical, laboratory, and radiological characteristics, as well as potential biomarkers for predicting disease severity in 2019-nCoV-infected patients in Shenzhen, China. All 12 cases of the 2019-nCoV-infected patients developed pneumonia and half of them developed acute respiratory distress syndrome (ARDS). The most common laboratory abnormalities were hypoalbuminemia, lymphopenia, decreased percentage of lymphocytes (LYM) and neutrophils (NEU), elevated C-reactive protein (CRP) and lactate dehydrogenase (LDH), and decreased CD8 count. The viral load of 2019-nCoV detected from patient respiratory tracts was positively linked to lung disease severity. ALB, LYM, LYM (%), LDH, NEU (%), and CRP were highly correlated to the acute lung injury. Age, viral load, lung injury score, and blood biochemistry indexes, albumin (ALB), CRP, LDH, LYM (%), LYM, and NEU (%), may be predictors of disease severity. Moreover, the Angiotensin II level in the plasma sample from 2019-nCoV infected patients was markedly elevated and linearly associated to viral load and lung injury. Our results suggest a number of potential diagnosis biomarkers and angiotensin receptor blocker (ARB) drugs for potential repurposing treatment of 2019-nCoV infection.

Novel H5N6 avian influenza virus reassortants with European H5N8 isolated in migratory birds, China

Five novel H5N6 influenza viruses, including four highly pathogenic avian influenza viruses and one low pathogenic avian influenza virus, were isolated from migratory birds in Ningxia, China, in November 2017. To understand the genetic origination of the novel H5N6 virus, and the infectivity and pathogenicity of the four highly pathogenic avian influenza viruses in mammals, phylogeographic analyses and infection studies in mice were performed. The phylogenetic and phylogeographic analyses showed that the H5N6 isolates, which are closely related to the viruses from Korea, Japan and the Netherlands, originated from reassortant virus between H5N8 and HxN6 viruses from western Russia. The animal study revealed that the SBD-87 isolate presented moderate virulence in mice, suggesting a potential public risk to humans and a potential threat to public health.

Ergosterol peroxide suppresses influenza A virus-induced pro-inflammatory response and apoptosis by blocking RIG-I signaling

Ergosterol peroxide has been shown to exhibit anti-tumor, antioxidant and anti-bacterial properties. However, the effects of ergosterol peroxide isolated from the herbal Baphicacanthus cusia root on influenza virus infection remain poorly understood. In the present study, ergosterol peroxide (compound 22) was obtained from the B. cusia root and subjected to investigation regarding its immunoregulatory effect on influenza A virus (IAV)-induced inflammation in A549 human alveolar epithelial cells. The structure of compound 22 isolated from B. cusia root. was elucidated by NMR analyses. Structure determination showed that the chemical structure of compound 22 closely resembles that of ergosterol peroxide. We observed that ergosterol peroxide treatment significantly suppressed IAV-induced upregulation of RIG-I expression. Additionally, ergosterol peroxide inhibited the activation of RIG-I downstream signaling pathways, including p38 MAP kinase and NF-κB, which ultimately resulted in the reduced production of an array of pro-inflammatory mediators and interferons (IFN-β and IFN-λ1). Interestingly, inhibitory effects of ergosterol peroxide on the expression of IFNs did not affect the expression of antiviral effectors or enhance viral replication. On the other hand, ergosterol peroxide effectively abolished the amplified production of pro-inflammatory mediators in cells pretreated with IFN-β (500 ng/ml) prior to IAV infection. Moreover, Annexin V and Hoechst 33258 staining revealed that increased apoptosis of IAV-infected cells was reversed by the presence of ergosterol peroxide. Our findings suggest that ergosterol peroxide from the B. cusia root suppressed IAV-associated inflammation and apoptosis via blocking RIG-I signaling, which may serve as a supplementary approach to the treatment of influenza.

Antigenic Variation of Avian Influenza A(H5N6) Viruses, Guangdong Province, China, 2014-2018

Market surveillance showed continuing circulation of avian influenza A(H5N6) virus in live poultry markets in Guangdong Province in 2017, despite compulsory vaccination for avian influenza A(H5Nx) and A(H7N9). We analyzed H5N6 viruses from 2014-2018 from Guangdong Province, revealing antigenic drift and decreased antibody response against the vaccine strain in vaccinated chickens.

B cell epitopes in the intrinsically disordered regions of neuraminidase and hemagglutinin proteins of H5N1 and H9N2 avian influenza viruses for peptide-based vaccine development

Avian influenza viruses (AIV) are very active in several parts of the globe and are the cause of huge economic loss for the poultry industry and also human fatalities. Three dimensional modeling was carried out for neuraminidase (NA) and hemagglutinin (HA) proteins of AIV. The C-score, estimated TM-Score, and estimated root-mean-square deviation (RMSD) score for NA of H5N1 were -1.18, 0.57 ± 0.15, and 9.8 ± 7.6, respectively. The C-score, estimated TM-Score, and estimated RMSD score for NA of H9N2 were -1.43, 0.54 ± 0.15, and 10.5 ± 4.6, respectively. The C-score, estimated TM-Score, and estimated RMSD score for HA of H5N1 were -0.03, 0.71 ± 0.12, and 7.7 ± 4.3, respectively. The C-score, estimated TM-Score, and estimated RMSD score for HA of H9N2 were -0.57, 0.64 ± 0.13, and 8.9 ± 4.6, respectively. Intrinsically disordered regions were identified for the NA and HA proteins of H5N1 and H9N2 with the use of PONDR program. Linear B cell epitope was predicted using BepiPred 2 program for NA and HA of H5N1 and H9N2 avian influenza strains. Discontinuous epitopes were predicted by Discotope 2 program. The linear epitopes that were considered likely to be immunogenic and within the intrinsically disordered region for the NA of H5N1 was TKSTNSRSGFEMIWDPNGWTGTDSSFSVK, and for H9N2 it was VGDTPRNDDSSSSSNCRDPNNERGAP. In the case of HA of H5N1, it was QRLVPKIATRSKVNGQSG and ATGLRNSPQRERRRKK; for H9N2 it was INRTFKPLIGPRPLVNGLQG and SLKLAVGLRNVPARSSR. The discontinuous epitopes of NA of H5N1 and H9N2 were identified at various regions of the protein structure spanning from amino acid residue positions 90 to 449 and 107 to 469, respectively. Similarly, the discontinuous epitopes of HA of H5N1 and H9N2 were identified in the amino acid residue positions 27 to 517 and 136 to 521, respectively. This study has identified potential and highly immunogenic linear and conformational B-cell epitopes towards developing a vaccine against AIV both for human and poultry use.

Avian influenza A (H9N2) virus infections among poultry workers, swine workers, and the general population in Beijing, China, 2013-2016: A serological cohort study

Background

Few studies have reported on the seroprevalence of antibodies against avian influenza A (H9N2) virus and the incidence of these infections in the northern China and among swine workers.

Methods

We conducted a serological cohort study among people working with poultry or swine or the general population in Beijing, China. It comprised four cross‐sectional serological surveys in November 2013, April 2014, April 2015, and April 2016. Blood samples collected from the participants were tested for anti‐H9N2 antibodies using a hemagglutination‐inhibition (HI) assay. Multivariable Poisson regression model was then used to compare the person‐month incidence rates for H9N2 viral infections among the three groups, assessed by incidence rate ratio (IRR).

Results

In the four cross‐sectional surveys, the highest seroprevalence of anti‐H9N2 antibodies (HI titer ≥ 80) was recorded in the poultry workers (2.77%, 19/685) in April 2016, while the lowest was recorded in the general population (0.09%, 1/1135) in April 2015. The highest incidence density rate for H9N2 infections across the whole study period was recorded among the poultry workers (3.75/1000 person‐months), followed by the swine workers (1.94/1000 person‐months) and the general population (1.78/1000 person‐months). Multivariable analysis showed that the poultry workers were at higher risk (IRR: 2.42, 95% CI: 1.07‐5.48; P = 0.034) of contracting H9N2 virus than the general population.

Conclusions

Although the seroprevalence of H9N2 antibodies was low in Beijing, the poultry workers were at higher risk of contracting H9N2 viral infections than the general population. Closer monitoring and strengthened protection measures for poultry workers are warranted.

Avian influenza overview May - August 2018

Between 16 May and 15 August 2018, three highly pathogenic avian influenza (HPAI) A(H5N8) outbreaks in poultry establishments and three HPAI A(H5N6) outbreaks in wild birds were reported in Europe. Three low pathogenic avian influenza (LPAI) outbreaks were reported in three Member States. Few HPAI and LPAI bird cases have been detected in this period of the year, in accordance with the seasonal expected pattern of LPAI and HPAI. There is no evidence to date that HPAI A(H5N8) and A(H5N6) viruses circulating in Europe have caused any human infections. The risk of zoonotic transmission to the general public in Europe is considered to be very low. Several HPAI outbreaks in poultry were reported during this period from Russia. The presence of the A(H5N2) and A(H5N8) viruses in parts of Russia connected with fall migration routes of wild birds is of concern for possible introduction and spread with wild birds migrating to the EU. Although few AI outbreaks were observed in Africa, Asia and the Middle East during the reporting period, the probability of AI virus introductions from non‐EU countries via wild birds particularly via the north‐eastern route from Russia is increasing, as the fall migration of wild birds will start in the coming weeks. Further, the lower temperatures in autumn and winter may facilitate the environmental survival of avian influenza viruses potentially introduced to Europe.