Acute respiratory infections are the most common illnesses experienced by people of all ages worldwide. Previous epidemiologic studies have shown that viruses cause most of these acute respiratory illnesses[1]. Among respiratory viruses,

Da-Yan Wang,1 Shun-Xiang Qi,1 Xi-Yan Li, Jun-Feng Guo, Min-Ju Tan, Guang-Yue Han, Yan-Fang Liu, Yu Lan, Lei Yang, Wei-Juan Huang, Yan-Hui Cheng, Xiang Zhao, Tian Bai, Zhao Wang, He-Jiang Wei, Ning Xiao, and Yue-Long Shu Authors affiliations: National Institute for Viral Disease Control and Prevention, China CDC, Beijing, People’s Republic of China (D.-Y. Wang, X.-Y. Li, J.-F. Guo, M.-J. Tan, Y. Lan, L. Yang, W.-J. Huang, Y.-H. Cheng, X. Zhao, T. Bai, Z. Wang, N. Xiao, H.-J. Wei, Y.-L. Shu); and Hebei Center for Disease Control and Prevention, Hebei Province, People’s Republic of China (S.-X. Qi, G.-Y. Han, Y.-F. Liu)

Seasonal influenza A (H3N2) virus has been a concern since its first introduction in humans in 1968. Accumulating antigenic changes in viral hemagglutinin (HA), particularly recent cocirculations of multiple HA genetic clades, allow H3N2 virus evade into humans annually. From 2010, the binding of neuraminidase (NA) to sialic acid made the traditional assay for HA inhibition antibodies (Abs) unsuitable for antigenicity characterization. Here, we investigated the serum anti-NA response in a cohort with a seroconversion of microneutralizing (MN) Abs targeting the circulating strain, A/Singapore/INFIMH-16-0019/2016 (H3N2, 3C.2a1)-like, a virus during 2018/2019 flu seasons. We discovered that MN Ab titers show no difference between children and adults. Nevertheless, higher titers of Abs with NA activity inhibition (NI) activity of 129 and seroconversion rate of 68.42% are presented in children aged 7-17 years (n = 19) and 73.47 and 41.17% in adults aged 21-59 years (n = 17), respectively. The MN Abs generated in children display direct correlations with HA- and NA-binding Abs or NI Abs. The NI activity exhibited cross-reactivity to N2 of H3N2 viruses of 2007 and 2013, commonly with 329-N-glycosylation and E344 in N2, a characteristic of earlier 3C.2a H3N2 virus in 2014. The percentage of such viruses pronouncedly decreased and was even replaced by those dominant H3N2 viruses with E344K and 329 non-glycosylation, which have a significantly low activity to the tested antisera. Our findings suggest that NI assay is a testable assay applied in H3N2 infection in children, and the antigenic drift of current N2 should be considered for vaccine selection.

Friction stir processing is a solid-state welding technology capable of joining metal parts without the melting. The microstructure of the material evolved during the process vary from columnar grain along the thermal gradient in the melt pool to fine equiaxed grains. Evaluation on its mechanical properties in terms of micro-hardness was performed. A significant decrease in microhardness was observed in the processed region. The decrease in the microhardness is mainly attributed to the dissolution of hardening precipitates in the aluminium matrix.

干扰素诱导跨膜蛋白3 (Interferon-induced transmembrane protein 3,IFITM3)的单核苷酸突变位点(Single-nucleotide polymorphism,SNP) rs12252-C在中国人群的比例高,与流感病毒H1N1/09感染后疾病的严重性相关.本文主要探索流感病毒三价灭活疫苗(Trivalent inactivated vaccine,TIV)免疫IFITM3敲除小鼠后机体免疫反应的变化.采用转录激活因子样效应物核酸酶(Transcription activator-like effector nucleases,TALENs)技术构建IFITM3敲除小鼠模型,TIV肌肉注射免疫小鼠,使用流式细胞术检测小鼠脾脏的获得性免疫细胞,如T细胞、B细胞,以及固有免疫细胞,如自然杀伤细胞(Natural killer cell,NK细胞)、树突状细胞(Dendritic cell,DC)、巨噬细胞(Macrophage,Mφ)、中性粒细胞等的数量变化情况.TIV免疫后7d,IFIMT3敲除小鼠脾脏CD8+T细胞、NK细胞的数量和活化水平升高,生发中心(Germinal center,GC)的B细胞数量下降,CD4+T细胞、DC、Mφ、中性粒细胞的数量没有显著变化.本研究提示,IFITM3敲除影响了TIV免疫后小鼠脾脏免疫细胞的数量和活化水平,为IFITM3与免疫反应的关系研究奠定了基础.

Objective In China, 24 cases of human infection with highly pathogenic avian influenza (HPAI) H5N6 virus have been confirmed since the first confirmed case in 2014. Therefore, we developed and assessed two H5N6 candidate vaccine viruses (CVVs). Methods In accordance with the World Health Organization (WHO) recommendations, we constructed two reassortant viruses using reverse genetics (RG) technology to match the two different epidemic H5N6 viruses. We performed complete genome sequencing to determine the genetic stability. We assessed the growth ability of the studied viruses in MDCK cells and conducted a hemagglutination inhibition assay to analyze their antigenicity. Pathogenicity attenuation was also evaluated in vitro and in vivo. Results The results showed that no mutations occurred in hemagglutinin or neuraminidase, and both CVVs retained their original antigenicity. The replication capacity of the two CVVs reached a level similar to that of A/Puerto Rico/8/34 in MDCK cells. The two CVVs showed low pathogenicity in vitro and in vivo, which are in line with the WHO requirements for CVVs. Conclusion We obtained two genetically stable CVVs of HPAI H5N6 with high growth characteristics, which may aid in our preparedness for a potential H5N6 pandemic.

Interferon-induced transmembrane protein 3 (IFITM3) as an antiviral factor can inhibit replication of several viruses including influenza virus. A single-nucleotide polymorphism rs12252-C of IFITM3 results in a truncated IFITM3 protein lacking its first 21 amino acids, which is much higher in the Han Chinese population and associated with severe illness in adults infected with pandemic influenza H1N1/09 virus. To investigate if IFITM3 or IFITM3 rs12252-C could affect the antibody response after influenza vaccination, we detected the haemagglutination inhibition (HI) of 171 healthy young adult volunteers (IFITM3 rs12252-C/C, C/T, T/T carriers) and in an IFITM3-deletion mouse model (Ifitm3(-/-)) after trivalent inactivated vaccine (TIV) immunization. Seroconversion rates for H1N1, H3N2 and B viruses in IFITM3 rs12252-C/C genotype carriers was lower compared with C/T and T/T donors. Significantly lower levels of specific antibodies to H1N1, H3N2 and B viruses and total IgG were observed in Ifitm3(-/-) mice. Correspondingly, the numbers of splenic germinal centre (GC) B cells, plasma cells, TIV-specific IgG(+) antibody secreting cells and T follicular helper cells in Ifitm3(-/-) mice were lower compared with wild type mice. However, the number of memory B cells was higher in Ifitm3(-/-) mice at day 7 after booster. The HI level of Ifitm3(-/-) mice remained lower than WT mice after third vaccination. Moreover, the transcriptional network regulating GC B cell and plasma cell differentiation was abnormal in Ifitm3(-/-) mice. Our results indicate that IFITM3 deletion attenuated the antibody response. The mechanism of influenza-IFITM3 interactions affecting the antibody response requires further investigation.

Objective Interferon-induced transmembrane protein 3 (IFITM3) is an important member of the IFITM family. However, the molecular mechanisms underlying its antiviral action have not been completely elucidated. Recent studies on IFITM3, particularly those focused on innate antiviral defense mechanisms, have shown that IFITM3 affects the body's adaptive immune response. The aim of this study was to determine the contribution of IFITM3 proteins to immune control of influenza infection in vivo. Methods We performed proteomics, flow cytometry, and immunohistochemistry analysis and used bioinformatics tools to systematically compare and analyze the differences in natural killer (NK) cell numbers, their activation, and their immune function in the lungs of Ifitm3-/- and wild-type mice. Results Ifitm3-/- mice developed more severe inflammation and apoptotic responses compared to wild-type mice. Moreover, the NK cell activation was higher in the lungs of Ifitm3-/- mice during acute influenza infection. Conclusions Based on our results, we speculate that the NK cells are more readily activated in the absence of IFITM3, increasing mortality in Ifitm3-/- mice.

Since the first confirmed case of H7N9 infection was reported in China, there have been five epidemic waves of human H7N9 infections between 2013 and 2017. The fifth wave differed from the previous four waves in that highly pathogenic avian influenza (HPAI) H7N9 viruses with multiple basic amino acids at the cleavage site were detected in humans, poultry and environmental samples. The HPAI H7N9 viruses were genetically and antigenically distinct from previous H7N9 viruses. Therefore, a new candidate vaccine virus(CVV) derived from a HPAI A/Guangdong/17SF003/2016-like virus was proposed by the World Health Organization(WHO). According to the WHO recommendations, we constructed a new CVV using reverse genetic technology, with a (6+2) gene constitution. The (6+2) reassortant virus possessed hemagglutinin(HA) with multiple basic amino acids removed and the neuraminidase from A/Guangdong/SF003/2016 in a high-yield A/Puerto Rico/8/34 virus backbone. Sequence analysis confirmed that no mutations had occurred in the HA of V1E1(the initial CVV rescued in Vero cells and followed by passage in eggs), but a mixture of arginine (R)/glycine (G)/isoleucine (I) was detected at position 220 (H3 numbering) in the HA of V1E2 to V1E5 with different percentages. Furthermore, V1E5 showed improved growth characteristics and immunogenicity compared with V1E1, and retained low pathogenicity in chickens and chicken embryos, but the mutation changed its antigenicity. Our study indicates that antigenic changes should be closely monitored during the development of H7N9 CVV in eggs. Additionally, although V1E5 changes the antigenicity, the antisera had some reactivity to previous H7N9 CVVs.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Human Infection with a Novel Avian-Origin Influenza A (H7N9) Virus. Rongbao Gao, Bin Cao, Yunwen Hu, Zijian Feng, Dayan Wang, Wanfu Hu, Jian Chen, Zhijun Jie, Haibo Qiu, Ke Xu, et al.

Eurasian avian-like H1N1 (EA H1N1) swine influenza viruses (SIVs) have become predominant in pig populations in China and have recently been reported to have the most potential to raise the next pandemic in humans. The mutation D701N in the PB2 protein, which accounts for 31% of H1N1 SIVs, has previously been shown to contribute to the adaptation of the highly pathogenic H5N1 or H7N7 avian influenza viruses in mammals. However, little is known of the effects of this substitution on the EA H1N1 viruses. Herein, we investigated the contributions of 701N in the PB2 protein to an EA H1N1 SIV (A/Hunan/42443/2015(H1N1), HuN EA-H1N1), which had 701D in the PB2 protein. Our results found that viral polymerase activity, viral replication, and pathogenicity in mice were indeed enhanced due to the introduction of 701N into the PB2 protein, and the increased viral growth was partly mediated by the host factor importin-α7. Thus, substantial attention should be paid to the D701N mutation in pig populations.

The H9N2 avian influenza virus circulates worldwide, predominantly in poultry. Its increasing infectivity and adaptation in poultry and mammals have enhanced the possibility of human infection. However, H9N2 human cases are difficult to detect due to their mild clinical symptoms. Serological study is valuable for risk assessment. A total of 15,700 serum samples were collected from occupationally exposed populations in 22 provinces of China and tested using hemagglutination inhibition (HI) and microneutralization (MN) assays. The sera positive rate of A/Guangzhou/333/99 (G9) was significantly higher than that of A/quail/Hong Kong/G1/97 (G1) (p<0.0001). The seroprevalences of H9N2 were significantly higher in live poultry market workers, large-scale poultry farmers and backyard farmers than in poultry slaughtering factory workers and wild bird habitant workers. The seroprevalences of A/Guangzhou/333/99 (G9) (3.42%) and A/quail/Hong Kong/G1/97 (G1) (1.37%) in Southern China were significantly higher than those in Northern China (p<0.001). The seroprevalence was highest in the elderly, followed by adults and then youths. Our results indicate that subclinical human infection with H9N2 avian influenza virus is widely distributed in China. Longer poultry exposure might contribute to the higher seroprevalence in the elderly group. The higher seroprevalence observed in Southern China than in Northern China might be caused by a higher poultry density.

We wished to study the association between Interferon-induced transmembrane protein 3 (IFITM 3) rs12252 single nucleotide polymorphism(SNP) and the clinical severity of infection by the influenza B virus(IBV).A total of 264 EDTA blood samples were collected from patients with mild (181 samples) or severe(81 samples)IBV infection confirmed in the laboratory in the Jilin and Hunan Provinces of China.Simultaneously,103 people of Chinese Han ethnicity in a population in Beijing (CHB) were selected as the control group.Genome DNA was extracted from blood samples and the corresponding fragment was amplified by the polymerase chain reaction(PCR).The genotype of IFTIM3 rs12252 was detected by the Sanger sequencing method.There was no significant difference infrequency distribution of the IFITM 3 rs12252 genotype between mild cases and the general population.However,the genotype frequencywas significantly different in severe cases compared with the general population.The proportion of the IFITM3 rs12252 CC genotype in patients with severe IBVinfection was higher than that in mild cases.Hence,the rs12252 CC genotype was associated with severe infection by the IBV.

A new Al-Al2O3-CNTs Composite has been successfully fabricated using friction stir processing. Uniform dispersion of nano-particles in the metal matrix was observed. Significant improvement in the micro-hardness and tensile strengths were obtained through the addition of nano particles. In particular the yield strength of the composites increased 70% compared with that of friction stir processed Al when both Al2O3 and CNTs were added in the matrix. The improvement in the mechanical properties is mainly attributed to grain refinement and Zener pinning effect caused by the addition of nano-sized particles. Al2O3 particles were observed at the bottom of the dimples at the fracture site, suggesting voids initiation at the Al/Al2O3 interfaces regions. The reinforcing mechanism with multiple nano-particles addition was discussed therein.

Aluminium reinforced with multi-wall carbon nanotubes was produced using friction stir processing and selective laser melting. Very fine grains were successfully achieved in both methods with high Vickers hardness values. Cavities were present in selective laser melting of AlSi10Mg reinforced with multi-wall carbon nanotubes parts resulting in higher stress concentration brittle fracture appearance. The high laser absorption and higher thermal conductivity of multi-wall carbon nanotubes resulted in the formation of the cavities in the melted parts. However, the fractography images showed dimpled like appearance indicating a ductile fracture mechanism. Multi-wall carbon nanotubes were observed at the fracture sites indicating the presence of a crack-bridging mechanism. In comparison to carbon nanotubes reinforced aluminium by friction stir processing, selective laser melting produces aluminium reinforced aluminium with better mechanical properties.

Electrochemical polishing (ECP) was used to improve surface quality of Inconel 718 components fabricated by selective laser melting (SLM). In this study, SLM Inconel 718 tube part surface was processed by electrochemical polishing by pre-optimized parameters. The surface morphology and roughness evolution with different electrochemical polishing duration were characterized by scanning electron microscopy (SEM) and 3D surface profilometer. The surface roughness can reach as low as 3.66μm (Ra), compared with the initial surface roughness of 6.05μm. Microstructure and XRD study indicated that the δ and carbide phase were revealed under ECP with long duration instead of γ phases on the original sample surface. In order to identify the mechanical properties of the surface, nano-indentation tests were carried out on both the original sample surface and the sample surface after ECP. The results showed that the samples after ECP possess a relatively lower surface hardness and surface elastic modulus.

Preparation of maternal strain A/PR/8/34 HA antiserum for influenza virus classical reassortment. A/PR/8/34 virus was digested by bromelain after inactivation and purification. 5%-20% sucrose continuous density gradient centrifugation method was used to purify HA protein. SIRD method was used to select the target protein. SDS-PAGE method was used to identified HA protein. High Immunogenic A/PR/8/34 HA protein was successfully prepared and HI titer reached 10240. High purity HA antiserum was identified by SIRD method. The key reagent in the classical reassortment of influenza virus was prepared, and the complete set of technical methods were explored, which laid the foundation for the independent research and development of seasonal influenza vaccine strains of China.

AlSi10Mg reinforced with carbon nanotubes were fabricated using selective laser melting manufacturing process. The influence of laser power and scanning speed on the densification behavior and microhardness were studied. Near fully dense nanocomposite parts with 97% theoretical density were achieved with increasing energy density. Microhardness was observed to slightly decrease as energy density increases. This could be attributed to the increase in grain size as energy density increases.

制备流感病毒经典重配过程中所需的A/PR/8/34母本株血凝素蛋白（Hemagglutinin,HA）抗血清。A/PR/8/34流感病毒灭活纯化后经菠萝蛋白酶消化。5%~20%蔗糖连续密度梯度离心法纯化HA蛋白。单向免疫扩散法（Single Radial Immunodiffusion,SRID）筛选目的蛋白。SDS-PAGE法鉴定目的蛋白。纯化的A/PR/8/34 HA蛋白免疫兔子制备抗血清,血凝抑制试验（Hemoglutination Inhibition Assay,HI）测定HA抗血清效价,经SRID法鉴定HA抗血清纯度。成功制备了高免疫原性A/PR/8/34HA蛋白;兔抗血清HI滴度可达10240,SRID法鉴定为高纯度HA抗血清。制备了流感病毒经典重配中关键试剂,摸索成功整套技术方法,为我国自主研发季节性流感疫苗株奠定了基础。