Expression of influenza B virus hemagglutinin and its immunogenicity determination / 生物工程学报

Influenza B virus is one of the causes for seasonal influenza, which can account for serious illness or even death in some cases. We tested the expression of extracellular domain of hemagglutinin (HA-ecto) of influenza B viruses in mammalian cells, and then determined the immunogenicity of HA-ecto in mice. The gene sequence encoding influenza B virus HA-ecto, foldon sequence, and HIS tag was optimized and inserted into pCAGGS vector. The opening reading frame (ORF) of neuraminidase was also cloned into pCAGGS. The pCAGGS-HA-ecto and pCAGGS-NA were co-transfected into 293T cells using linear polyethylenimine. Cell supernatant after transfection was collected after 96 h, and the secreted trimmeric HA-ecto protein was purified by nickel ion affinity chromatography and size exclusion chromatography. Subsequently, the mice were immunized with HA-ecto protein, and the corresponding antibody titers were detected by ELISA and hemagglutination inhibition (HAI) assays. The results showed that soluble trimeric HA-ecto protein could be obtained using mammalian cell expression system. Moreover, trimeric HA-ecto protein, in combination with the adjuvant, induced high levels of ELISA and HAI antibodies against homogenous and heterologous antigens in mice. Thus, the soluble HA-ecto protein expressed in mammalian cells could be used as a recombinant subunit vaccine candidate for influenza B virus.

Avian influenza A (H7N9) virus: from low pathogenic to highly pathogenic / 医学前沿

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.

Establishment of a lethal mouse model of influenza B virus / 军事医学

Objective To establish a mouse lethal model of influenza B virus , which will facilitate the study on the mechanism of pathogenesis , transmission of influenza B virus , development of new vaccines and drugs against influenza B virus.Methods We obtained a mouse adaptive B/Lee/1940 virus by continuously passaging it in mice for 5 cycles.The P5 virus was propagated in MDCK cells , which was used for infecting mice .The body mass and survival rate of mice were monitored during the following 14 days after infection.At the same time,the 8 gene segments (PB2, PB1, PA, HA, NA/NB, NP, M, and NS) of P0 and P5 virus were sequenced and analyzed .Results and Conclusion Virus was detected in the lungs of mice in each generation in the process of virus passaging .The body mass of mice infected with the deadly mouse adaptive virus changed dramatically .The mortality of mice was 100%, and virus was detected in mouse lungs . Sequence analysis results indicated that the amino acid mutations occurred in PB 2 and NP.A series of experiments indicated that we had established a mouse lethal model of influenza B virus .

Structural vaccinology: structure-based design of influenza A virus hemagglutinin subtype-specific subunit vaccines

There is a great need for new vaccine development against influenza A viruses due to the drawbacks of traditional vaccines that are mainly prepared using embryonated eggs. The main component of the current split influenza A virus vaccine is viral hemagglutinin (HA) which induces a strong antibody-mediated immune response. To develop a modern vaccine against influenza A viruses, the current research has been focused on the universal vaccines targeting viral M2, NP and HA proteins. Crystallographic studies have shown that HA forms a trimer embedded on the viral envelope surface, and each monomer consists of a globular head (HA1) and a "rod-like" stalk region (HA2), the latter being more conserved among different HA subtypes and being the primary target for universal vaccines. In this study, we rationally designed the HA head based on the crystal structure of the 2009-pandemic influenza A (H1N1) virus HA as a model, tested its immunogenicity in mice, solved its crystal structure and further examined its immunological characteristics. The results show that the HA globular head can be easily prepared by in vitro refolding in an E. coli expression system, which maintains its intact structure and allows for the stimulation of a strong immune response. Together with recent reports on some similar HA globular head preparations we conclude that structure-based rational design of the HA globular head can be used for subtype-specific vaccines against influenza viruses.

The research on making use of hemophan dialyzer in the application of heparin-free hemodialysis / 中国实用护理杂志

0.05).Every one of the patients completed hemodialysis except one needing to rebuild blood circulation by changing another dialyzer, whose vein pressure became higher and the dislyzer was of cruor as it was difficult to build blood circulation. The rate of success has reached 99 percent. Conclusion There is no influence upon the general cruor mechanism when using hemophan dialyzers to heparin-free hemodialysis treat the acute or chronic renal failure. This simple method is not only effective but also safe, which can provide a reliable measure to rescue patients suffering from acute or chronic renal failure with serious tendency of hemorrhage.