Cross-neutralizing Anti-hemagglutinin Antibodies Isolated from Patients Infected with Avian Influenza A (H5N1) Virus / 生物医学与环境科学（英文）

Objective@#To recover broad-neutralizing monoclonal antibodies (BnAbs) from avian influenza A (H5N1) virus infection cases and investigate their genetic and functional features.@*Methods@#We screened the Abs repertoires of expanded B cells circulating in the peripheral blood of H5N1 patients. The genetic basis, biological functions, and epitopes of the obtained BnAbs were assessed and modeled.@*Results@#Two BnAbs, 2-12D5, and 3-37G7.1, were respectively obtained from two human H5N1 cases on days 12 and 21 after disease onset. Both Abs demonstrated cross-neutralizing and Ab-dependent cellular cytotoxicity (ADCC) activity. Albeit derived from distinct Ab lineages, , V 1-69-D2-15-J 4 (2-12D5) and V 1-2-D3-9-J 5 (3-32G7.1), the BnAbs were directed toward CR6261-like epitopes in the HA stem, and HA I45 in the hydrophobic pocket was the critical residue for their binding. Signature motifs for binding with the HA stem, namely, IFY in V 1-69-encoded Abs and LXYFXW in D3-9-encoded Abs, were also observed in 2-12D5 and 3-32G7.1, respectively.@*Conclusions@#Cross-reactive B cells of different germline origins could be activated and re-circulated by avian influenza virus. The HA stem epitopes targeted by the BnAbs, and the two Ab-encoding genes usage implied the VH1-69 and D3-9 are the ideal candidates triggered by influenza virus for vaccine development.

Epidemiology of Sepsis-3 in a sub-district of Beijing: secondary analysis of a population-based database / 中华医学杂志(英文版)

Background@#With the publication of Sepsis-3 definition, epidemiological data based on Sepsis-3 definition from middle-income countries including China are scarce, which prohibits understanding of the disease burden of this newly defined syndrome in these settings. The purpose of this study was to describe incidence and outcome of Sepsis-3 in Yuetan sub-district of Beijing and to estimate the incidence rate of Sepsis-3 in China.@*Methods@#The medical records of all adult residents hospitalized from July 1, 2012 to June 30, 2014 in Yuetan sub-district of Beijing were reviewed. Patients with sepsis-3 and severe sepsis/septic shock were identified. The incidence rates and mortality rate of sepsis-3 and sepsis/septic shock were calculated, incidence rates and in-hospital mortality rates were normalized to the population distribution in the 2010 National Census. Population incidence rate and case fatality rate between sexes were compared with the Z test, as the data conformed to Poisson distribution.@*Results@#Of the 21,191 hospitalized patients, 935 patients were diagnosed with Sepsis-3, and 498 cases met severe sepsis/septic shock criteria. The crude annual incidence rate of Sepsis-3 in Yuetan sub-district was 363 cases per 100,000 population, corresponding to standardized incidence rates of 236 cases per 100,000 population per year, respectively. The overall case fatality rate of Sepsis-3 was 32.0%, the crude population mortality rates of Sepsis-3 was 116 cases per 100,000 population per year, the standardized mortality rate was 67 cases per 100,000 population per year, corresponding to a speculative extrapolation of 700,437 deaths in China. The incidence rate and mortality rate of Sepsis-3 were significantly higher in males, elderly people, and patients with more comorbidities. The 62.1% of patients with Sepsis-3 had community-acquired infections, compared with 75.3% of infected patients without Sepsis-3 (P < 0.001). The most common infection in patients with Sepsis-3 was lower respiratory tract infection. When compared with patients with Sepsis-3, patients diagnosed as severe sepsis/septic shock were more likely to have higher case fatality rate (53.4% vs. 32.0%, P < 0.001)@*Conclusions@#This study found the standardized incidence rate of 236 cases per 100,000 person-year for Sepsis-3, which was more common in males and elderly population. This corresponded to about 2.5 million new cases of Sepsis-3 per year, resulting in more than 700,000 deaths in China.@*Clinical trial registration@#NCT02285257, https://clinicaltrials.gov/ct2/show/record/NCT02285257.

Epidemiology of Sepsis-3 in a sub-district of Beijing: secondary analysis of a population-based database / 中华医学杂志(英文版)

BACKGROUND@#With the publication of Sepsis-3 definition, epidemiological data based on Sepsis-3 definition from middle-income countries including China are scarce, which prohibits understanding of the disease burden of this newly defined syndrome in these settings. The purpose of this study was to describe incidence and outcome of Sepsis-3 in Yuetan sub-district of Beijing and to estimate the incidence rate of Sepsis-3 in China.@*METHODS@#The medical records of all adult residents hospitalized from July 1, 2012 to June 30, 2014 in Yuetan sub-district of Beijing were reviewed. Patients with sepsis-3 and severe sepsis/septic shock were identified. The incidence rates and mortality rate of sepsis-3 and sepsis/septic shock were calculated, incidence rates and in-hospital mortality rates were normalized to the population distribution in the 2010 National Census. Population incidence rate and case fatality rate between sexes were compared with the Z test, as the data conformed to Poisson distribution.@*RESULTS@#Of the 21,191 hospitalized patients, 935 patients were diagnosed with Sepsis-3, and 498 cases met severe sepsis/septic shock criteria. The crude annual incidence rate of Sepsis-3 in Yuetan sub-district was 363 cases per 100,000 population, corresponding to standardized incidence rates of 236 cases per 100,000 population per year, respectively. The overall case fatality rate of Sepsis-3 was 32.0%, the crude population mortality rates of Sepsis-3 was 116 cases per 100,000 population per year, the standardized mortality rate was 67 cases per 100,000 population per year, corresponding to a speculative extrapolation of 700,437 deaths in China. The incidence rate and mortality rate of Sepsis-3 were significantly higher in males, elderly people, and patients with more comorbidities. The 62.1% of patients with Sepsis-3 had community-acquired infections, compared with 75.3% of infected patients without Sepsis-3 (P < 0.001). The most common infection in patients with Sepsis-3 was lower respiratory tract infection. When compared with patients with Sepsis-3, patients diagnosed as severe sepsis/septic shock were more likely to have higher case fatality rate (53.4% vs. 32.0%, P < 0.001) CONCLUSIONS:: This study found the standardized incidence rate of 236 cases per 100,000 person-year for Sepsis-3, which was more common in males and elderly population. This corresponded to about 2.5 million new cases of Sepsis-3 per year, resulting in more than 700,000 deaths in China.@*CLINICAL TRIAL REGISTRATION@#NCT02285257, https://clinicaltrials.gov/ct2/show/record/NCT02285257.

Advances in research and development of universal influenza vaccines / 病毒学报

Vaccination is the primary strategy for the prevention and control of pandemic influenza. Because influenza virus is highly variable across strains, universal influenza vaccines need to be developed to address this problem. This review describes the research progress in conserved epitopes of influenza virus, the advances in the research and development of universal influenza vaccines based on the relatively conserved sequences of NP, M2e, HA2, and headless HA, the mechanisms of cross-protection, and the methods to improve cross-protection.

Preliminary study of a universal vaccine based on the HA2 protein of the H5N1 influenza virus / 病毒学报

Fragments encoding amino acids 76-130 in the linear conserved region (LCR) of A/Hubei/1/2010 (H5N1) HA2 was fused to hepatitis B core antigen (HBc) to generate a LCR-HBe virus-like particle (VLP). Results showed that the fusion protein of LCR-HBc was highly expressed in this prokaryotic expression system. The purified LCR-HBc particle stimulated high levels of IgG production in mice with a titer of > 1:12 800, and provided 50% cross-protection against lethal challenge by H1N1 viruses.

Accessing the features of surface neuraminidase (N1) of influenza A virus presenting on the platforms for anti-NA Abs screening / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To understand if the Neuraminidase (N1) of Influenza A virus at the surface of yeast-displaying system, eukaryotic expression system and the infected cells could be used for anti-NA Abs screening, their activities and bindings to five candidate Abs were assayed.</p><p><b>METHODS</b>The surface NA expression was obtained by transfecting by recombinant NA constructors with specific tag-labels or live virus infection. The functional activity was measured by the fluorescent assay. Their bindings to the Abs were detected by flow cytometry.</p><p><b>RESULTS</b>The surface NAs presenting on the yeast-displaying system and eukaryotic expression system exhibited functional NA activities as the NA at the surface of virus-infected cells which showed affinities to Ab1, 4, and 5. The same bindings to Abl and 5 were found in the surface NA expressed by eukaryotic expression system while minor binding was observed in the yeast displayed-NA.</p><p><b>CONCLUSION</b>The epitopes of yeast-displayed NA may be different from the NAs present at eukaryotic expression system and the infected cells which more likely suitable for the screening of anti-NA Abs.</p>

Evaluation of influenza A virus nucleoprotein based on baculovirus surface-display technology / 病毒学报

Nucleoprotein (NP) of influenza virus is highly conserved and type-specific. NP can trigger strong cell-mediated immune responses in host and is involved in the protection against the challenges with different subtype influenza viruses. Here, NP of an avian H5N1 (A/Hubei/1/2010, HB) was expressed by baculovirus surface-display technology and its immunogenicity as well as protective mechanism was investigated in mice infection model. Western blot and immunolabeled electron microscopy assay showed NP was displayed on baculovirus surface. ELISA results showed NP could induce high level of anti-NP IgG in the sera from NP-Bac-inoculated mice. Two cellular immune peptides (NP57-74 IQNSITIERMVLSAFDER and NP441-458 RTEIIKMMESARPEDLSF) were identified by IFN-gamma ELISPOT assay. NP57-66 and NP441-450 and NP protein could be able to trigger the activation of CD4+ and CD8+ T cells, and the response of CD8+ T was more predominant. The challenge study of mice-adapted virus A/PR/8/34 (H1N1) showed that NP-Bac could reduce viral load and attenuate the damage to lung tissue. 50% protection ratio against the virus could be detected.

Identification of dual receptor-binding specific strains of human H5N1 viruses in China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Both the 2, 6 linkage and its topology on target cells are critical for the recognition by human influenza virus. The binding preference of avian flu virus H5N1 HA to the 2, 3-linked sialylated glycans is considered the major factor limiting its efficient infection and transmission in humans. To monitor potential adaptation of H5N1 virus in human population, the surveillance of receptor-binding specificity was undertaken in China.</p><p><b>METHODS</b>The binding specificity of 32 human H5N1 virus strains isolated from 2003 to 2009 was tested by 2, 3-specific sialidase-treated chicken red blood cell (CRBC) agglutination assay and a solid-phase direct binding assay with synthetic sialylglycopolymers.</p><p><b>RESULTS</b>Dual binding preference to 2, 3 and 2, 6-glycans were found in two strains: A/Guangdong/1/06 (A/GD/1/06) and A/Guangxi/1/08 (A/GX/1/08). Though minor effect of short-2, 6-binding was detected in A/GX/1/08 at a low virus titer, both showed high affinity to the oligosaccharide at a high load. Notably both are of the long-2, 6-recognition, with the same topology as that of human H1N1 and H3N2 viruses.</p><p><b>CONCLUSION</b>The findings suggest that human H5N1 virus in China likely acquired the potential human-adaptation ability. Further research and surveillance on receptor-binding specificity of H5N1 viruses are required.</p>

Neuraminidase inhibitors resistance in influenza viruses and the related mechanisms / 病毒学报

Influenza viruses are highly contagious for human population and result in acute respiratory infectious diseases ranging from mild to severe. Neuraminidase (NA) inhibitors (NAIs) (oseltamivir, zanamivir, peramivir and laninamivir), which target the NA glycoproteins of influenza A and B viruses are widely used in the prophylaxis and treatment of influenza virus infection. However, the substitutions of amino acids in NA or HA gene may lead to resistances to NAIs. NAI-resistance-related substitutions are typically specific to certain NA type or subtype. The sensitivity for NAI-resistance detection is affected by different assays used.

The proliferation of H1N1 subtype influenza viruses in A549 and BEAS-2B cells / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>Analyze the proliferation of different host H1N1 subtype influenza viruses in A549 and BEAS-2B cells.</p><p><b>METHODS</b>Human, avain and swine three hosts of the H1N1 influenza viruses infected A549 and BEAS-2B cells and analyze the characteristics of different periods after inocubation. Determine the receptor binding specificity of influenza virus by hemagglutination (HA) test with RBCs with two types of receptor. And the receptors on surfaces of A549 and BEAS-2B cells were tested by flow cytometry.</p><p><b>RESULTS</b>The Cell Pathologic Effect (CPE) is obvious after 24 h inoculation in A549 cells by all the H1N1 influenza viruses, moreover, the peak hemagglutinin (HA) and 50% tissue culture cell infected dose (TCID50) titers was observed after 36 h of culturing in A549 cells. Otherwise, the CPE is not typical from 24 h-120 h inoculated by the same viruses and the HA, TCID50 titers were keep low all the periods in the BEAS-2B cell after inoculation. The receptor-binding preference of H1N1 viruses used in the study was screened by HA assay and some were found with 2-6-receptor binding affinity. Both SA a-2, 3Gal and SA a-2, 6Gal receptors were detected on A549 and BEAS-2B, furthermore, receptor density on A549 cells was significantly higher than that of BEAS-2B cells.</p><p><b>CONCLUSION</b>A549 cells were susceptible to human, avian and swine H1N1 influenza viruses infection and permissively for viral replication. However, BEASE-2B cells with similar receptor pattern and epithelium-derived propriety as A549 cells were unsusceptible to their infection and replication. Possible host factors involved in effective viral infection and replication were needed further study.</p>

The immunogenicity in mice enhanced significantly via prime-boost vaccination with DNA-based or recombinant vaccinia(Tiantan) viral-based H5N1 vaccine candidates containing multi-structural antigens / 病毒学报

This study aimed to develop an effective experimental vaccine against highly pathogenic H5N1 Avian Influenza (HPAI) virus and to optimize their immunization programs. As reported previously, various DNA-based or recombinant vaccinia viral(Tiantan)-based H5N1 vaccine candidates, which containing a single cistronic construct (HAop, or NAop) or a bicistronic construct (HAop/M2 or NAop/M1) of H5N1 influenza virus (Anhui strain) were constructed and characterized in our lab. In this study, we further analysed the immunogenicity in mice of these vaccine candidates by various protocols (single or combined immunization). Our results showed that: comparing with immunization with DNA-based or rTTV-based H5N1 vaccine only, combined DNA-based with rTTV-based H5N1 vaccine immunization via prime-boost strategy enhanced immune response significantly against multi-H5N1 antigens detected by hemagglutination inhibition (HI) assay, NA- or M1- or M2-specific antibody detection, and micro-neutralizing antibody test and IFN-gamma ELISpot assay. Priming with DNA-based vaccine induced higher level of humoral response against HA or NA antigen than priming with rTTV-based vaccine; In contract, M1 and M2-specific antibody levels were higher among that of priming with rTTV -based vaccine. These findings provide a basis for further development of novel H5N1 vaccines and for the optimization of the immunization programs of combined multi-antigens vaccine candidates.

Establishment of a mouse-lethal model for pandemic H1N1 influenza virus / 病毒学报

To establish the mouse-lethal model for pandemic H1N1 influenza virus, provide an animal model for studying the pathogenicity and host adaptation of 2009 pandemic H1N1 influenza virus, and find out the key amino acid mutations which may affect viral virulence and replication. A pandemic H1N1 influenza virus strain, A/Sichuan/SWL1/2009 (H1N1, SC/1) was passaged in mouse lung by 15 cycles with intranasal infection. The passaged viruses were all propagated in MDCK cells and sequenced. Based on the sequencing results, four mice in each group were inoculated with 6 selected viruses and their weight and survival rate were monitored during the following 14 days after infection. Additionally, SC/1-MA P14 and P15 viruses were sequenced after purification by Plague Assay. Viral virulence was increased after serial passages and the mortality of 100% was detected after 7 passages. Several amino acid residue mutations of passaged viruses which may contribute to the enhanced virulence were observed. The increased virulence of passaged viruses and mammalian host adaptation maybe associated with amino acid mutations in viral functional proteins. Finally, we established a mouse-lethal model.

Gene expression profiles comparison between 2009 pandemic and seasonal H1N1 influenza viruses in A549 cells / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To perform gene expression profiles comparison so that to identify and understand the potential differences in pathogenesis between the pandemic and seasonal A (H1N1) influenza viruses.</p><p><b>METHODS</b>A549 cells were infected with A/California/07/09 (H1N1) and A/GuangdongBaoan/51/08 (H1N1) respectively at the same MOI of 2 and collected at 2, 4, 8, and 24 h post infection (p.i.). Gene expression profiles of A549 cells were obtained using the 22 K Human Genome Oligo Array, and differentially expressed genes were analyzed at selected time points.</p><p><b>RESULTS</b>Microarrays results indicated that both of the viruses suppressed host immune response related pathways including cytokine production while pandemic H1N1 virus displayed weaker suppression of host immune response than seasonal H1N1 virus. Observation on similar anti-apoptotic events such as activation of apoptosis inhibitor and down-regulation of key genes of apoptosis pathways in both infections showed that activities of promoting apoptosis were different in later stage of infection.</p><p><b>CONCLUSIONS</b>The immuno-suppression and anti-apoptosis events of pandemic H1N1 virus were similar to those seen by seasonal H1N1 virus. The pandemic H1N1 virus had an ability to inhibit biological pathways associated with cytokine responses, NK activation and macrophage recognition.</p>

DNA vaccination via in vivo electroporation can elicit specific immune response against highly pathogenic H5N1 influenza viral structural antigens in mice / 病毒学报

This study aims to develop inexpensive and effective experimental vaccines against highly pathogenic H5N1 Avian Influenza (HPAI) virus and to optimize their immunization programs. To this end, we first synthesized the codon-optimized hemagglutinin gene (HAop) and neuraminidase gene (NAop), both of which were derived from a H5N1 virus (Anhui strain), and constructed successfully the DNA vaccines containing a single cistronic construct (HAwt, HAop, or NAop) or a bicistronic construct (HAop/M2 or NAop/M1) of H5N1 influenza virus origin. Their expression was confirmed by indirect immunofluorescent assay (IFA) and Western blotting. Then twice vaccination of mice with the DNA vaccines by injection intramuscularly or in vivo electroporation (EP) via two different routes was evaluated and analyzed by hemagglutination inhibition (HI) assay, NA-specific antibody detection, micro-neutralizing antibody test and IFN-gamma ELISpot assay. Our results showed that the DNA vaccines with coden-optimized HAop and NAop constructs could quickly elicit a strong immune response by in vivo EP, especially the cellular immune response against HA and NA; the in vivo EP via intradermal route induced stronger humoral immune responses than those via intramuscular route. Our findings will pave a way for further development of novel DNA-based H5N1 vaccine and for the optimization of the immunization programs of DNA vaccine.

Construction of recombinant adenovirus co-expressing M1 and HA genes of influenza virus type A / 病毒学报

Based on the human H5N1 influenza virus strain A/Anhui/1/2005, recombinant adenovirus co-expressing M1 and HA genes of H5N1 influenza virus was constructed using an internal ribosome entry site (IRES) sequence to link the two genes. The M1 and HA genes of H5N1 influenza virus were amplified by PCR and subcloned into pStar vector separately. Then the M1-IRES-HA fragment was amplified and subcloned into pShuttle-CMV vector, the shuttle plasmid was then linearized and transformed into BJ5183 bacteria which contained backbone vector pAd-Easy. The recombinant vector pAd-Easy was packaged in 293 cells to get recombinant adenovirus Ad-M1/HA. CPE was observed after 293 cells were transfected by Ad-M1/HA. The co-expression of M1 and HA genes was confirmed by Western-blot and IFA (immunofluorescence assay). The IRES containing recombinant adenovirus allowed functional co-expression of M1 and HA genes and provided the foundation for developing new influenza vaccines with adenoviral vector.

The differential expression of the human lung carcinoma cells infected with high pathogenic avian influenza virus A/Anhui/1/2005 (H5N1) / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To identify genes in human cells infected with high pathogenic avian influenza viruses H5N1.</p><p><b>METHODS</b>The lung carcinoma cells line A549 was infected with H5N1 and H1N1, respectively. We harvested the infected cells at the different time points after infection and screened the genes with differential expression via microarray technology. The candidate genes were selected and confirmed by quantitative real-time PCR.</p><p><b>RESULTS</b>The spectrum of genes with the differential expression in the cells infected with H5N1 was obtained and 16 candidate genes were identified in the cellular apoptosis pathway, mTOR pathway, and the cellular immunity as well.</p><p><b>CONCLUSIONS</b>Our results suggest that H5N1 exert a stronger impact on eliciting apoptosis of infected cells than the common influenza virus H1N1.</p>

Influence of avian influenza virus NS1 protein on the expression of IP-10 in BEAS-2B cells / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the influence of avian influenza virus (AIV) NS1 protein on the expression of interferon-inducible protein 10 (IP-10).</p><p><b>METHODS</b>NSI gene from virus A/Anhui/1/2005 (H5N1), NS1 gene inserted with 80-84 amino acids from virus A/Anhui/1/2005 (H5N1) and NS1 gene from virus A/Puerto Rico/8/1934 (H1N1) were cloned into the eukaryotic expression vector pEGFP-N1, and transfected into BEAS-2B cells, IP-10 expression level in transfected cells was detected by flow cytometry.</p><p><b>RESULTS</b>Compared with the control group pEGFP-N1, expression of these three different NS1 genes can down-regulate the expression of IP-10 in BEAS-2B cells, but there is no significant difference as to the lower level among them.</p><p><b>CONCLUSION</b>NS1 protein of A/Anhui/1/2005 (H5N1) can down-regulate the expression level of IP-10, but this may not clarify its relationship with the virulence of AIV.</p>