Enhanced Protective Efficacy of H5 Subtype Influenza Vaccine with Modification of the Multibasic Cleavage Site of Hemagglutinin in Retroviral Pseudotypes

Traditionally, the multibasic cleavage site （MBCS） of surface protein H5-hemagglutinin （HA） is converted to a monobasic one so as to weaken the virulence of recombinant H5N1 influenza viruses and to produce inactivated and live attenuated vaccines. Whether such modification benefits new candidate vaccines has not been adequately investigated. We previously used retroviral vectors to generate wtH5N1 pseudotypes containing the wild-type HA （wtH5） from A/swine/Anhui/ca/2004 （H5N1） virus. Here, we generated mtH5N1 pseudotypes, which contained a mutant-type HA （mtH5） with a modified monobasic cleavage site. Groups of mice were subcutaneously injected with the two types of influenza pseudotypes. Compared to the group immunized with wtH5N1 pseudotypes, the inoculation of mtH5N1 pseudotypes induced significantly higher levels of HA specific IgG and IFN-y in immunized mice, and enhanced protection against the challenge of mouse-adapted avian influenza virus A/Chicken/Henardl2/2004 （H5N1）. This study suggests modification of the H5-hemagglutinin MBCS in retroviral pseudotypes enhances protection efficacy in mice and this information may be helpful for development of vaccines from mammalian cells to fight against H5N 1 influenza viruses.

Research and industrialization of near-net rolling technology used in shaft parts

Shaft part rolling is an efficient and green near- net shaping technology offering many advantages, includ- ing high production efficiency, high material utilization rate, high product quality, and excellent production environment. In this paper, the features of shaft part rolling are introduced along with the working principles of two main shaft part rolling technologies, namely, cross wedge rolling （CWR） and skew rolling （SR）. In relation to this technology, some R＆D achievements gained by the University of Science and Technology Beijing are summarized. Finally, the latest developments in shaft part rolling are presented, including SR steel bails, precise forming of camshaft blank by CWR, SR phosphorous copper balls at room temperature, and CWR hollow axle sleeve. Although the shaft part rolling technology has been widely used in China, it only accounts for about 15% of applicable parts at present. Nevertheless, this technology has broad application prospects.

Baculovirus Surface Display of Zika Virus Envelope Protein Protects against Virus Challenge in Mouse Model

Zika virus(ZIKV)is emerging as a significant pathogen worldwide and may cause severe neurological disorders such as fetal microcephaly and Guillain-Barre syndrome.No drug or listed vaccines are currently available for preventing ZIKV infection.As a major target of neutralizing,ZIKV envelop(E)protein usually used for vaccine development.Nevertheless,the immunogenicity of ZIKV envelop(E)protein expressed by baculovirus display system has never been assessed.In this study,we reported a new strategy for surface display of ZIKV E protein by a recombinant baculovirus vector derived from Autographa californica multiple nuclear polyhedrosis virus(AcMNPV)and assessed its immunogenicity in mice.We produced recombinant fusion ZIKV E protein linked with signal peptide(SP)and transmembrane domain(TM)of AcMNPV GP64.The results showed that the recombinant protein was easy to produce by baculovirus display system.BALB/c mice immunized with this recombinant E protein developed ZIKV specific serum antibodies.The anti-E protein sera from the mice were able to effectively neutralize ZIKV in vitro.More importantly,AG6(IFN-a/b and IFN-c receptor deficient)mice immunized with recombinant E protein were protected against lethal ZIKV challenge.Together,thesefindings demonstrated that the recombinant E protein displayed by baculovirus can be conveniently prepared and displayed good immunogenicity in immunized mice.It is a promising practical approach for prompting the development of vaccine and related immunology research.

Recovery of a Far-Eastern Strain of Tick-Borne Encephalitis Virus with a Full-Length Infectious cDNA Clone

Tick-borne encephalitis virus(TBEV) is a pathogenic virus known to cause central nervous system(CNS) diseases in humans, and has become an increasing public health threat nowadays. The rates of TBEV infection in the endemic countries are increasing. However, there is no effective antiviral against the disease. This underscores the urgent need for tools to study the emergence and pathogenesis of TBEV and to accelerate the development of vaccines and antivirals. In this study, we reported an infectious c DNA clone of TBEV that was isolated in China(the WH2012 strain). A beta-globin intron was inserted in the coding region of nonstructural protein 1(NS1) gene to improve the stability of viral genome in bacteria. In mammalian cells, the inserted intron was excised and spliced precisely, which did not lead to the generation of inserted mutants. High titers of infectious progeny viruses were generated after the transfection of the infectious clone. The cDNA-derived TBEV replicated efficiently, and caused typical cytopathic effect(CPE) and plaques in BHK-21 cells. In addition, the CPE and growth curve of cDNA-derived virus were similar to that of its parental isolate in cells. Together, we have constructed the first infectious TBEV cDNA clone in China, and the clone can be used to investigate the genetic determinants of TBEV virulence and disease pathogenesis, and to develop countermeasures against the virus.

Development of a biosensor assessing SARS-CoV-2 main protease proteolytic activity in living cells for antiviral drugs screening

Dear Editor,The Coronavirus disease 2019(COVID-19)pandemic is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).The genome of this virus encodes two overlapping polyproteins,pp1a and pp1ab(Wu et al.,2020;Zhou et al.,2020).The functional polypeptides are released from those two polyproteins by extensive proteolytic events.

Epidemiological,Clinical and Serological Characteristics of Children with Coronavirus Disease 2019 in Wuhan:A Single-centered,Retrospective Study

Dear Editor,In December 2019,SARS-Co V-2 was first detected in the samples obtained from three adult patients who suffered from an unknown viral pneumonia in Wuhan(Li et al.2020).This unknown viral pneumonia is further named as coronavirus disease 2019(COVID-19)by the World Health Organization.

An improved method for identifying SUMOylation sites of viral proteins

Dear Editor, In recent years, post-translational modifications （PTMs） by small ubiquitin-related modifiers （SUMOs） have emerged as an important regulatory mechanism for both cellular and viral processes （Ribet and Cossart, 2010）. Identifying the SUMOylation sites of the target protein is important to understand the molecular mechanism under- lying SUMO modification and virus-host interactions, as well as provide new insights into antiviral drug develop- ment （Wimmer and Schreiner, 2015）. Traditional site- directed mutagenesis for identifying viral protein SUMO- ylation sites lacks a specific aim and is laborious （McManus et al., 2016）. Recently, mass spectrometry （MS） has been employed as an accurate and sensitive tool to identify PTM sites, thereby greatly expanding the number of known SUMOylated proteins （Pedrioli et al., 2006）. However, during viral infection, SUMOylation is highly dynamic and SUMOylated viral proteins often have low abundance, which makes studying SUMOylation under natural conditions difficult.

Associations of land use around rail transit stations with jobs-housing distribution of rail commuters from smart-card data

Previous studies generally used land use and travel flow to investigate the efficiency of the railway system in Transit-Oriented Development(TOD)cities.Furthermore,to study the association of land use and jobs-housing distribution of commuters,we can find out the potential development of rail commuting.In this research,four railway lines in Wuhan,China,were selected to explore the land use in promoting practical commuting population according to the smart-card data obtained.For land use issues,except the road density and building density,a Normalized Location-Weighted Landscape Index(NLWLI)based on the source-sink theory in landscape ecology was established to assess the jobs-housing land use around rail transit stations.Meanwhile,employment and housing details of commuters around rail transit stations were identified using smart-card data.We found that the generation of commuting flow was affected by building density and the land use of employment in the immediate vicinity of rail transit stations.The distribution of building density and commuters in a mature rail line was roughly a normal distribution.However,due to the inconsistency of land use and jobs-housing distribution around stations,the requirement of the balance of land use and jobs-housing distribution should be reduced at the scale of rail stations in the TOD planning systems.This study is the application of massive smart-card data in the field of urban research.It identifies land use issues that affect rail transit commuting flow,and can help urban planners improve the efficiency of rail transit through planning and design.