Bing du xue bao = Chinese journal of virology最新文献

Baculoviridae is a family of large, enveloped, double-stranded DNA viruses that mostly infect insects. Occlusion-derived virus is a baculovirus viral phenotype that induces primary infection when ingested by the insect host per os. Several occlusion-derived viral membrane proteins, called per os infectivity factors, have been shown to be essential for oral infectivity. Here, we review advances in structure and function studies of P74,which was the first PIF to be identified and has been extensively investigated.P74 contains two transmembrane domains in its hydrophobic C terminus which play a role in transmembrane anchoring, and two conserved domains which are involved in P74 function.P74is efficiently cleaved by an occlusion body endogenous alkaline protease and a host trypsin during baculovirus release and its digestion products are loosely associated with a stable complex formed by PIF1,PIF2 and PIF3.As a baculovirus attachment protein,P74 binds to a specific receptor of approximately 35 kDa in brush border membrane vesicles, facilitating the internalization of baculovirus into host cells. Knowledge of P74 will improve our understanding of baculovirus primary infection, which will support the design of nonchemical strategies to block baculovirus transmission or suppress pest populations.

According to the published chronic bee paralysis virus(CBPV)gene sequences, three specific primers were designed. Establish CBPV semi nested PCR detection method, the outer primer annealing temperatures(52,54,56 and 58℃),the Inner primer annealing temperatures(48,50,52 and 54℃),primer concentrations(0.1,0.2and 0.4 mmol/L)and volume of ExTaq enzyme (0.25,0.5and 1μL) for semi nested PCR were optimized, and the optimized method was verified for specificity and sensitivity. At the same time, Twenty clinical samples were tested by the developed semi nested PCR. The results show that the semi nested PCR outer primer annealing temperature, inner primer annealing temperature, primer concentration and volume of ExTaq enzyme were 56℃,50℃,0.2mmol/L and 0.25μL;no cross reactions with the cDNAs of healthy, CBPV, ABPV, CSBV, BQCV, DWV were observed by the developed semi nested PCR, with a minimun detection limit of 10-3 pg;4samples were positive from the 20 clinical samples. The established semi nested PCR detection was proved to be rapid, sensitive, specific, etc, which enable it a promising clinical diagnostic and epidemiological investigation method.

Due to the remarkable ability to target and kill tumor cells, genetically engineering HSV-1 has been widely studied for its potency in cancer treatment. Several oncolytic herpes simplex viruses had been proved to be clinically effective in different phases of clinical trials against multiple cancers, which can also induce good antitumor immunity. In 2015,Amgen′s T-VEC has been approved by FDA for the treatment of melanoma. The combination with the conventional therapies, such as radiotherapy and chemotherapy, can further enhance the efficacy of virotherapy. Moreover, Immune checkpoint blockade therapy has been proved to be a promising strategy to fight multiple cancers, the combination of immune activation using oncolytic viruses and immune checkpoint inhibitors is likely to usher in a new era of cancer treatment.

To evaluate the neutralizing potency and spectrum of three recombinant human mAbs CR57(Ⅰ), RV08(Ⅱ), RV3A5 (Ⅲ) and the triple combination cocktail against antigenic site I, II and III on rabies virus glycoprotein, a standard fluorescent antibody virus neutralization test(FAVN)on several RV vaccine strains, fixed strains, and street strains of total 11 trains was performed by incubation of RV with varying concentrations of antibody followed by incubation with BHK-21 cells. To investigate whether the antibodies display neutralizing activity against a lethal RV infection in vivo, we performed a Syrian hamster study by infecting with 50LD(50)/100μl of CVS-11 strain intramuscularly (i. m.) in the gastrocnemius muscle. Three recombinant human mAbs CR57 (I), RV08 (II), RV3A5 (III) and the compatibility triple cocktail showed broad cross-neutralizing reactivity to all 11 RV strains. The cocktail composed of three mAbs CR57 (Ⅰ) RV08 (Ⅱ), RV3A5 (Ⅲ) by neutralizing titers of 1 : 1 : 1 has no less in neutralizing ability against these strains, indicating that no mutual interference between the three antibodies. The cocktail exhibited neutralizing synergistic activity against individual strains(JX08-45,Flury,SRV9).The treatment with CR57,RV08,RV3A5 or the triple combination cocktail alone respectively provided better protection with a survival range of 100%against the lethal RV infection compared HRIG immunized alone. Combined immunization with the vaccine, recombinant mAbs protected hamsters with a survival rate of 100%equally as well as HRIG after exposure to a lethal RV infection. Our results provide more candidates eligible for use in a mAb cocktail aimed at replacing RIG for rabies post-exposure prophylaxis.

To explore the genomic characterization of 4vaccine-derived poliovirus(VDPV)strains isolated from 2acute flaccid paralysis(AFP)cases in Yunnan Province in 2010 and 2012,respectively,the complete genome sequences of the 4strains were determined. Sequence analysis revealed that the complete genome length of the type Ⅱ and type Ⅰ VDPV was 7439nt and 7441 nt, respectively. Nucleotide and amino acid sequence similarities of type II VDPV were 95.4% and 97.7%,respectively,and type I VDPV were93.9% and 97.9%,respectively as compared with those of Sabin strains. Nucleotide substitutions were found at two important attenuation sites (nt 481 and nt in type Ⅱ VDPV, and three important attenuation sites(nt480,nt2795 and nt6203)in type I VDPV. Type 2 and type 1VDPV strains had 1.0% and2.3% divergence with Sabin strains, respectively. Similarity plot analysis showed multiple recombination events in the genome of the 4strains,which showed that the recombination was common and complex. Analysis of the characteristics of VDPVs on molecular level could provide valuable information on evolutionary dynamics and lay foundation for developing scientific and feasible strategy to control VDPV.

This study explored risk assessment and genotyping of hepatitis A virus(HAV)in fruit and vegetable products. Two hundred and sixteen samples of fruit and vegetable products were examined by real-time RT-PCR. Six samples tested positive for hepatitis A virus, including frozen strawberries, frozen blueberries, frozen diced potatoes, frozen diced apple and frozen raspberries, accounting for 2.8% of the total samples tested. These six HAV isolates were genotyped by nested RT-PCR amplification, and a single band was detected in isolates from frozen diced apple(210-1999)and frozen blueberries(210-2002).These two isolates belong to the HAV IB subtype, based on analysis of evolution and homology. This study provides HAV risk information for fruit and vegetable enterprises and food safety management departments. Furthermore, it lays a foundation for HAV traceability, and provides technical support to ensure product safety for enterprises at critical control points including planting, harvest, processing and packaging. These results provide reliable data for epidemiological diagnosis.

Respiratory syndrome coronavirus in the Middle East (MERS-Co V) has caused wide attention since it was discovered, and the design of effective vaccines for MERS-Co V becomes a hot area at present. Therefore, this review is aimed at novel research progress of the recombinant vaccine for MERS-Co V, including selection and improvement of animal model for vaccine test,construction and optimization of recombinant subunit vaccine, attempts at recombinant live vector vaccine based on varies of vectors, as well as the advantages of pseudovirus. In conclusion, we make a summary about the novel research progress of the recombinant vaccine for MERS-Co V and a promising prospect of its development in terms of both safety and effectiveness verification in the future will be demonstrated.

The purpose of this study was to express the matrix protein of rabies virus in baculovirus expression system and prepare its polyclonal antibody. Using the total RNA of RABV strain BD06 as a template, RT-PCR technique was utilized to amplify the sequence of M gene, which were then inserted into shuttle vector pFastbac I to construct the recombinant vector pFastbac I-M. After identification using the double restriction endonuclease cleavage method, the recombinant vector pFastbac I-M were transformed into the competent E. coli DH10 Bac to construct the recombinant expression vector Bacmid-M, which were transfected into Sf9 cells mediated by lipofectamine 2000 to obtain the recombinant baculovirus AcMNPV-M. The mice anti-His monoclonal antibody, rabbit anti-RV positive serum and canine anti-RV positive serum were used in Western Blot assays to identify the expression and reactogenicity of the recombinant. The recombinant M protein were purified under denaturing conditions using the nickel iron affinity chromatography column, then used to immunize the New Zealand White rabbit to prepare its polyclonal antibody. Western Blot assay and FAVN assay were used to validate the polyclonal antibody. Our results showed that the M protein of RABV were successfully expressed in baculovirus expression system,of which molecular weight was of about 25kD;the recombinant M protein has a good reactogenicity and immunogenicity; the rabbit polyclonal antibody prepared by purification of M protein could react with the M protein of RABV strain BD06,SRV 9,CVS-24,ERA,PV2061 and aG. Undoubtedly, the successfully preparation of both recombinant M protein and its polyclonal antibody support a material foundation for further study on the properties of M protein of RABV.

To assess the significance of environmental surveillance in the control and prevention of viral gastroenteritis, we analyzed the molecular characteristics of norovirus (NoV), rotavirus(RV),and human astrovirus (HAstV), sequences detected in domestic sewage. Environmental sewage monitoring sites were set up in three cities in Shandong, China. RNA was extracted from seven sewage samples collected each year from 2009 to 2015.RT-PCR detection of norovirus, rotavirus, and human astrovirus was performed. Positive PCR segments were cloned into a T-vector, transformed and sequenced, and genotyping and phylogenic analysis performed. A total of 210 viral sequences belonging to 6NoV I,4NoV II,3RV G,3RV P and 4HAstV were obtained.GI.2,GII.4,G9,P[8],and HAstV-1were the most frequently detected types. Phylogenetic analysis revealed multiple transmission chains in the genotypes of GI.3,GI.6,GII.4,G9,P[8],HAstV-1,and HAstV-4.The results showed not only that sewage contains dramatic information regarding gastroenteritis viruses, but also that environmental surveillance is an important approach in monitoring the regional circulation of specific viruses.

Middle East respiratory syndrome coronavirus (MERS-Co V) is a RNA virus causing serious harm to people. In order to investigate the codon usage characteristics and influence factors, codon preference and multivariate statistical analysis of MERS-Co V 9 gene sequences were performed by using Codon W, CUSP and SPSS software, getting the content of GC at three positions of codons, ENC (Effective number of codon)and RSCU(Relative synonymous codon usage)of all genes. In addition, the results were compared with Escherichia coli, yeast and human’s codon usage frequency. The results showed that GC3 content is significantly lower than GC1 and GC2content,and less than 50%.It indicates that the third position of codons prefers to A or T.ENC value is 50.59,which implies codon usage bias is a little slight in MERS-Co V genome. According to the neutral drawing analysis and ENC-plot analysis, codon bias is mainly affected by selection pressure in the MERS-Co V genome. It is found that codon usage frequency of MERS-Co V is more close to yeast, compared with other three kinds of biological codon usage frequency.Finally,19 codons are defined as the major preference codons in MERS-Co V. The results have a certain significance for MERS-Co V that selecting gene expression host system, contributing further to development of genetically engineered vaccine and therapeutic antibody.