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Objective:To construct a novel respiratory syncytial virus (RSV) vaccine based on a recombinant influenza virus vector and evaluate its immune protective effects in mice.Methods:A recombinant H1N1 influenza A virus (IAV) expressing the extracellular domain (Gecto) of RSV A2 G protein was constructed and rescued, named as PR8NAGecto/WSN. After in vitro verification of the Gecto expression and PR8NAGecto/WSN growth kinetics, a single dose of PR8NAGecto/WSN was used to immunize BALB/c mice through intranasal administration to evaluate the efficacy of PR8NAGecto/WSN by assessing humoral (IgG, neutralizing antibody), mucosal (IgA) and cellular immunity (IFN-γ ELISPOT). Four weeks after immunization, the mice were challenged with RSV A2 or RSV B9320 to evaluate the protective effects of PR8NAGecto/WSN by analyzing mouse body weight changes, lung tissue virus titers and pathological changes. Results:A single-dose intranasal immunization with PR8NAGecto/WSN induced robust humoral, mucosal and cellular immunity in mice. Moreover, the mice in the immunized group had lower lung virus loads and mild lung pathological damages following the challenge with RSV A or RSV B subtype as compared with the control group.Conclusions:A single-dose intranasal immunization with PR8NAGecto/WSN induces robust immunity and provide protection against RSV A and B challenges in mice. This study provides new ideas and reference for the development of novel mucosal vaccines against RSV.
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Objective:To construct recombinant influenza viruses expressing Gaussia luciferase (Gluc) with different influenza virus backbones and analyze their growth characteristics, genetic stability, ability to express Gluc and in vitro anti-influenza drug activity. Methods:The C-terminal of PR8NA was modified by inserting the porcine teschovirus-2A autocleavage peptide (P2A) and the Gluc-coding gene. Recombinant viruses, PR8NAGluc/PR8 and PR8NAGluc/WSN, were rescued using the eight-plasmid system of influenza virus reverse genetics, with seven plasmids derived from A/Puerto Rico/8/34(PR8) (H1N1) and A/WSN/1933 (WSN) H1N1. The genetic stability of the recombinant viruses was verified by RT-PCR. The fluorescence activity and the growth kinetics of the two recombinant viruses were compared. The correlation between the fluorescence activity of PR8NAGluc/WSN and median tissue culture infective dose (TCID 50), and the anti-drug activity of PR8NAGluc/WSN against oseltamivir, favipiravir, and Lianhua Qingwen in vitro were also analyzed. Results:The Gluc-expressing recombinant viruses constructed using PR8 and WSN backbones were successfully rescued by reverse genetics. Compared with the PR8 backbone, the WSN backbone significantly improved the fluorescence activity of Gluc. Moreover, the PR8NAGluc/WSN virus expressed stably in embryonated egg, and its replication kinetics was slightly lower than that of wild type. The fluorescence activity of PR8NAGluc/WSN virus had a good correlation with its TCID 50. The PR8NAGluc/WSN virus was sensitive to oseltamivir, favipiravir and Lianhua Qingwen. Conclusions:The recombinant virus with a WSN backbone exhibited higher fluorescence expression intensity as compared with the recombinant virus with a PR8 backbone. This study provided reference for high-throughput screening of anti-influenza drugs and the development of influenza virus vector vaccines.
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Objective:To evaluate the in vitro cross-neutralization of serum antibodies in human and mice immunized with inactivated SARS-CoV-2 vaccine against Delta and Beta variants. Methods:Human serum samples after a second and a third dose of inactivated SARS-CoV-2 vaccine and mouse serum samples after a two-dose vaccination were collected. The neutralizing antibodies in the samples against SARS-CoV-2 strains of prototype, Delta and Beta variants were detected using micro-neutralization assay in biosafety level Ⅲ laboratory. The seroconversion rates and geometric mean titers (GMTs) of antibodies were calculated.Results:The seroconversion rates of antibodies in human serum samples against different SARS-CoV-2 strains were all above 95%. After two-dose vaccination, the GMTs of neutralizing antibodies against the prototype, Delta and Beta strains were 109, 41 and 15, respectively. The GMTs decreased by 2.7 folds and 7.3 folds for the Delta and Beta variants as compared with the prototype strain. After the booster vaccination, the GMTs of neutralizing antibodies against the prototype, Delta and Beta strains were 446, 190 and 86, respectively. The GMTs of neutralizing antibodies against Delta and Beta variants decreased by 2.3 folds and 5.2 folds as compared with that against the prototype strain. The seroconversion rates of antibodies against different SARS-CoV-2 strains in mouse serum samples were all 100%. The GMTs of neutralizing antibodies against the prototype, Delta and Beta strains were 2 037, 862 and 408, respectively. The GMTs decreased by 2.4 folds and 5.0 folds for the Delta and Beta variants.Conclusions:Inactivated SARS-CoV-2 vaccine could induce a certain level of neutralizing antibodies against Delta and Beta variants in both human and mouse models. Moreover, a third dose of vaccine induced higher levels of neutralizing antibodies against Delta and Beta variants in human. This study provided valuable data for the clinical application and protective evaluation of the inactivated SARS-CoV-2 vaccine.
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Objective:To evaluate the performance of two commercial EIA kits for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing antibodies.Methods:Two commercial SARS-CoV-2 neutralizing antibody ELISA test kits (A and B) were used to detect serum panel consists of the following sera: 44 collected before vaccination, 120 collected one month after vaccination and 64 collected six months after recovery from convalescent patients of COVID-19. In the meantime, the above samples were also taken for live virus micro-neutralization test (micro-NT) indicated as the 50% neutralization antibody titer (NT 50). The consistency of qualitative and quantitative results between the two commercial kits and live virus neutralization test was analyzed. Results:Taking the micro-NT results as the standard, the positive coincidence rates of A and B kits were 97.40% and 100.00%, respectively; the negative coincidence rates were 97.30% and 95.95%, respectively; the Youden indices were 0.95 and 0.96, respectively. Furthermore, quantitative analysis indicated that the correlation coefficients between A and B kits and micro-NT results were 0.24 ( P<0.05) and 0.52 ( P<0.000 1) for samples collected after vaccination, respectively; while the correlation coefficients were 0.81 ( P<0.000 1) and 0.89 ( P<0.000 1) for convalescent serum samples, respectively. Conclusions:The results obtained by the two commercial neutralizing antibody detection kits were in good agreement with the qualitative results of micro-NT. The neutralizing antibody titers in convalescent serum samples detected by the two kits showed a stronger correlation with the micro-NT results.
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Objective:To construct a bivalent DNA vaccine against SARS-CoV-2 and influenza A virus H3N2 and to evaluate its immunogenicity in mice.Methods:The coding sequences for spike 1 (S1) protein of SARS-CoV-2 Beta variant and hemagglutinin (HA) of influenza A virus Cambodia (H3N2) strain were codon-optimized and synthesized. The two coding genes were ligated by the self-cleaving 2A peptide using over-lapping PCR to construct S1-2A-HA fragment, which was inserted into pVRC vector to construct the bivalent DNA vaccine, named as pVRC-S1-2A-HA. Indirect immunofluorescence assay (IFA) and Western blot were performed to detect the expression of S1 and HA proteins. BALB/c mice were immunized with pVRC-S1-2A-HA by intramuscular injection and electroporation. The humoral immune responses induced in mice were detected by indirect ELISA, pseudovirus neutralization assay and hemagglutination inhibition assay. Cellular immune responses were detected by IFN-γ ELISPOT, intracellular cytokine staining (ICS) and cytometric bead array (CBA).Results:The bivalent DNA vaccine pVRC-S1-2A-HA could express S1 and HA proteins in vitro. Specific cellular immune responses against S1 protein and specific IgG antibody against HA protein were significantly induced in mice with single-dose immunization. The antigen-specific immunity was significantly enhanced after booster immunization. The geometric mean titer (GMT) of specific IgG antibody increased to 3 251 for S1 protein and 45 407 for HA protein after two-dose immunization. Moreover, the S1-specific T cells increased to 1 238 SFC/10 6 cells. ICS results indicated that the booster vaccination induced CD4 + T and CD8 + T cells to produce IL-2, IFN-γ and TNF-α in mice. The secretion of various cytokines including IL-2, IL- 4, IL-6, IL-10 and IFN-γ in mouse splenocytes was induced after single-dose immunization. Conclusions:A bivalent DNA vaccine against SARS-CoV-2 and influenza A virus H3N2 was constructed and could induce S1- and HA-specific humoral and cellular immune responses in mice, suggesting the great potential of it for further development and application.
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Objective:To improve the consistency of test results through reducing inter-laboratory variation in SARS-CoV-2 antibody detection with WHO SARS-CoV-2 antibody candidate international standard (IS, sample G) and antibody reference panel (samples E, F, H, I, J).Methods:Ten WHO samples (A-J) including the candidate IS and reference panel were evaluated using different methods, such as microneutralization tests based on live SARS-CoV-2, pseudovirus neutralization assay and commercial ELISA kits. The test results were compared using statistical analysis.Results:Using IS (sample G) as a reference, the relative concentrations of other samples could be determined with less variation. ELISA and pseudovirus neutralization assay had consistent results with those obtained with the microneutralization test based on SARS-COV-2 strain HB02. Weakly positive samples could be detected only by a certain kit.Conclusions:The availability of an IS for antibodies would facilitate the standardization of SARS-CoV-2 antibody detection methods. The reference panel fitted all the assays based on the SARS-CoV-2 prototype Wuhan strain. Pseudovirus neutralization assay and ELISA could be used as alternatives to live SARS-CoV-2-based neutralization test to some extent.
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Objective:To evaluate the immunogenicity of a novel influenza virus mRNA vaccine based on conserved antigens delivered by lipopolyplex (LPP) platform in a mouse model.Methods:Four copies of genes coding for extracellular domain of matrix 2 protein (M2e) and nucleoprotein (NP) of influenza A virus were synthetized after codon optimization. The fusion antigens were transcribed in vitro and delivered by LPP platform, named as LPP-4M2eNP. Expression of M2e and NP in eukaryotic cells was detected by immunofluorescence assay (IFA). BALB/c mice were inoculated intramuscularly twice with 10 μg or 30 μg LPP-4M2eNP vaccine at an interval of four weeks. Antibody response was detected by ELISA and cellular-mediated immunity (CMI) was detected by enzyme-linked immunospot assay (ELISPOT). Results:IFA showed that NP and M2e were expressed correctly in eukaryotic cells. Single dose immunization could induce significant antigen (NP, M2e)-specific CMI and antigen (NP, M2e)-specific antibody response was induced in mice with Th1 type bias after boost immunization. Moreover, NP-specific CMI was increased significantly after the second immunization, while no significant change in M2e-specific CMI was observed.Conclusions:Stronger CMI was triggered in mice by single dose of LPP-4M2eNP vaccine. Furthermore, robust humoral and cellular immune responses were induced after boost immunization. This study suggested that LPP-4M2eNP vaccine, which based on conserved antigen of influenza A and delivered by LPP platform, had great potential for development and application.
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Objective:To screen and identify H-2 d-restricted T cell epitopes in fusion (F) and attachment (G) glycoproteins of Nipah virus (NiV) in mice. Methods:The complete peptides (single peptide contains 15 amino acids, and 10 amino acids were repeated in the front and back peptides) derived from F and G antigens were mixed into peptide libraries. BALB/c mice were immunized with DNA vaccines expressing NiV F and G proteins alone and in combination. The full sequence peptide libraries of F and G antigens were mixed into peptide pools by matrix design, and spleen cells of immunized mice were collected and analyzed by IFN-γ ELISPOT assay to detect the dominant H-2 d-restricted epitope peptides. Results:Twelve dominant H-2 d-restricted peptides were screened from the F protein-specific peptide library and the 56th peptide produced the strongest reaction. Four dominant peptides were screened from the G protein-specific peptide library and the 72nd peptide produced the strongest reaction. Conclusions:In this study, 12 F antigen-specific and 4 G antigen-specific H-2 d restricted dominant T cell epitopes of NiV were screened and identified by IFN-γ ELISPOT, which could provide reference for immunological analysis of NiV and vaccine research.
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The persistent public health threat of infection with the Middle East respiratory syndrome coronavirus (MERS-CoV) highlights the need for an effective MERS-CoV vaccine. Previous studies have focused mainly on the receptor-binding domain (RBD) on the spike protein of MERS-CoV. Herein, we investigated the immunogenicity and protective potential of the recombinant N-terminal domain (rNTD) of spike proteins as a vaccine candidate. BALB/c mice vaccinated with 5 or 10µg of rNTD protein demonstrated a significant humoral immune response (serum IgG and neutralizing activity). Additionally, according to the enzyme-linked immunospot, intracellular cytokine staining, and cytometric bead array assays, significant and functional T-cell immunity was induced by 10µg of the rNTD vaccination with aluminum and CpG adjuvant. Furthermore, rNTD-immunized mice showed reduced lung abnormalities in a MERS-CoV-challenge mouse model transfected with an adenoviral vector expressing human DPP4, showing protection consistent with that found with rRBD vaccination. These data show that rNTD induced potent cellular immunity and antigen-specific neutralizing antibodies in mice and that it demonstrated protective capacity against a viral challenge, indicating that rNTD is a vaccine candidate against MERS-CoV infection.
Subject(s)
Coronavirus Infections/prevention & control , Middle East Respiratory Syndrome Coronavirus/immunology , Spike Glycoprotein, Coronavirus/immunology , Viral Vaccines/immunology , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Disease Models, Animal , Female , Immunoassay , Immunoglobulin G/blood , Lung/pathology , Mice, Inbred BALB C , Middle East Respiratory Syndrome Coronavirus/genetics , Spike Glycoprotein, Coronavirus/genetics , T-Lymphocytes/immunology , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/genetics , Vaccines, Synthetic/immunology , Viral Vaccines/administration & dosage , Viral Vaccines/geneticsABSTRACT
Objective:To evaluate the immunological efficacy of a novel DNA vaccine against West Nile virus (WNV) in a mouse model.Methods:A DNA vaccine VRC-prME expressing the precursor membrane (prM) and envelope protein (E) of WNV Xinjiang strain (XJ11129-3) was constructed and its ability to express virus-like particles was verified in vitro. C57BL/6 mice were immunized twice with VRC-prME via intramuscular injection combined with electroporation with an interval of four weeks. Enzyme-linked immunoassay (ELISA) was used to detect serum antibodies after immunization. WNV (NY99 strain) single-round infectious particles were used to detect neutralizing antibodies. Cellular immune responses were analyzed by enzyme-linked immunoblot assay (ELISPOT) and intracellular cytokine staining (ICS). Results:VRC-prME induced a strong Th1-biased antibody response in mice that could cross-neutralize the WNV (NY99 strain) single-round infectious particles two weeks after the boost immunization. Moreover, the vaccine also elicited antigen-specific multifunctional CD8 + T cell responses (IFN-γ, IL-2, TNF-α). Conclusions:The novel DNA vaccine prepared in this study, expressing the prME protein of WNV XJ11129-3 strain, could induce stronger humoral and cellular immune responses in mice, which was worthy of further research and development for the prevention of WNV infection in China.
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Objective:To establish and evaluate a rapid nucleic acid detection method for SARS-CoV-2 based on COYOTE ? Flash20 real-time fluorescent quantitative PCR instrument. Methods:A rapid reaction system was constructed by using specific primer and probe sets targeting ORF1ab and N gene of SARS-CoV-2, and the sensitivity and specificity of the system were verified. At the same time, 108 clinical samples of COVID-19 were used to evaluate the application of this method.Results:The detection method did not require nucleic acid extraction, and the manual operation time was only one minute. After the sample was sent to the system, the test could be completed in 30 minutes. The detection limit of this method was 4×10 2 copies/ml. It had no cross-reactivity with other human coronaviruses (including HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU1, SARS-CoV and MERS-CoV) and other respiratory viruses. The evaluation of clinical sample application showed that the total coincidence rate with the conventional RT-qPCR which required nucleic acid extraction was 98.15%. Conclusions:Through the application evaluation of the rapid fluorescent quantitative PCR method of SARS-CoV-2, it was found that the method was simple, fast, specific and sensitive, and it was suitable for real-time and rapid detection needs in varieties of situations.
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Chikungunya virus(CHIKV)is a member of the genus Alphavirus, family Togaviridae and transmitted to humans by Aedes aegypti and Aedes albopictus. It mainly causes Chikungunya fever (CHIKF) with high fever, rash and multiple arthritis/joint pain as the main clinical symptoms, and is a major public health threat of global concern. There is still no vaccine or effective antiviral drug against CHIKV. This review briefly summarized the genomic and epidemiological characteristics of CHIKV, features of immune response to major CHIKV antigens and latest progress in vaccine development.
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Objective:To study the effects of different pre-sequencing sample processing modes on the results of whole genome sequencing with high-throughput sequencing (HTS) by taking the largest RNA virus (human coronavirus, HCoV) as the representative.Methods:Cell-cultured human coronavirus HCoV-OC43 strains were used as the representative samples and divided into different groups based on pre-sequencing processing modes as follows: untreated group, DNase and RNase treatment before nucleic acid extraction group, DNase treatment after nucleic acid extraction group, and DNase and RNase treatment before nucleic acid extraction and DNase treatment after nucleic acid extraction group. Nucleic acid samples of each group were analyzed by direct RNA sequencing (without amplification) and DNA sequencing after sequence independent single primer amplification (SISPA), respectively.Results:No significant difference in viral genome coverage rates was observed between different groups. The highest genome coverage and sequencing accuracy were obtained in DNase treatment after nucleic acid extraction group by direct RNA sequencing, and the ratio of viral reads and the sequencing depth of each locus were effectively improved by SISPA amplification.Conclusions:This study provided an optimized technical strategy for whole genome sequencing of RNA viruses such as coronavirus.
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Zika virus ( ZIKV) infection may lead to some serious potential complications, such as neonatal microcephaly and Guillain-Barre syndrome. ZIKV epidemics have caused public panic and aroused global concern. World Health Organization ( WHO) has listed ZIKV infection as one of the public health emergencies of international concern. This paper focused on the progress in ZIKV detection methods, espe-cially in serological tests, and summarized the advantages and disadvantages of each method in practical ap-plication, aiming to provide technical reference for the prevention and control of Zika virus infection.
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Objective To rapidly establish a mouse model for optical imaging of the dynamical process of pseudotyped Middle East respiratory syndrome coronavirus (MERS-CoV) infection. Methods In vitro expression in HeLa cells and functions of hDPP4 encoded by recombinant adenovirus Ad5 and pseudo-typed MERS-CoV were verified. The recombinant adenovirus expressing hDPP4 (Ad5-hDPP4) was injected into BALB/ c mice, which were then injected with pseudotyped MERS-CoV expressing firefly luciferase at a titer of 3×107 TCID50(50％ tissue culture infective dose) via intrathoracic (I. T. ) or intraperitoneal (I. P. ) injection. MERS-CoV infection and tissue distribution were observed using optical imaging techniques. Re-sults hDPP4 and firefly luciferase were efficiently expressed in HeLa cells. In BALB/ c mice injected with Ad5-hDPP4 via I. P. , firefly luciferase expression were detected in abdomen between 48-96 h after pseudo-typed MERS-CoV infection. The expression of firely luciferase was also detected in chests of BALB/ c mice injected with Ad5-hDPP4 via I. T. around 48 h after pseudotyped MERS-CoV infection. Conclusions This study reported a simple and rapid method for establishing a mouse model for conveniently and dynamically monitoring pseudotyped MERS-CoV infection, which might provide an effective means for in vivo evaluation of neutralizing antibodies or entry inhibitors by visualization with optical imaging techniques.
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Influenza poses a serious threat to global public health and causes serious economic los-ses. Vaccination is the most effective measure to prevent influenza. However, the mismatch between the vac-cine strain and the epidemic strain, which results from antigenic drift and antigen conversion of influenza vi-rus, often invalidates the conventional vaccine stockpiles. mRNA vaccine is a relatively safe platform com-posed of nucleic acid. Improvements in genetic engineering technology and novel delivery systems have great-ly promoted the research and development of mRNA vaccines against influenza. mRNA vaccines are promis-ing candidates for the rapid and efficient prevention of seasonal influenza epidemics and influenza pandemics.
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Objective To establish an indirect enzyme-linked immunosorbent assay (ELISA)and to compare the efficiency of receptor binding domain (RBD) proteins in different forms for Middle East re-spiratory syndrome coronavirus (MERS-CoV) antibody detection. Methods The monomeric and trimeric forms of MERS-CoV RBD were expressed in Bac-insect cells, 293T cells and ExpiCHO-STM expression sys-tem and then purified. The purified RBD proteins were identified with native gel electrophoresis and Western blot. Then, an equal amount of each RBD protein was used as coating antigen to establish an ELISA for de-tecting MERS-CoV IgG titer. For comparison, the newly developed ELISA and the commercial MERS-CoV IgG antibody detection kit (Euroimmune with S1 as the coating antigen) were used to measure the MERS-CoV antibody reference panel supplied by World Health Organization (WHO). Results The purified mon-omeric and trimeric MERS-CoV RBD were successfully prepared using 293T cells and ExpiCHO-STM system. RBD antigens of different forms and from different systems could recognize MERS-CoV specific antibody without having any cross reaction with the sera from healthy adults. The in-house RBD-based ELISA had good detection consistency with the Euroimmune commercial kit. The positive samples showed higher and more concentrated values based on the RBD trimer than the monomer. Conclusions Novel indirect ELISA methods based on the monomeric and trimeric forms of RBD protein were established. The trimetric form-based ELISA achieved higher detection efficiency than the one using the monomer antigen, suggesting that it could be uses as a competent alternative to the commercial kit.
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Objective@#To establish an indirect enzyme-linked immunosorbent assay (ELISA)and to compare the efficiency of receptor binding domain (RBD) proteins in different forms for Middle East respiratory syndrome coronavirus (MERS-CoV) antibody detection.@*Methods@#The monomeric and trimeric forms of MERS-CoV RBD were expressed in Bac-insect cells, 293T cells and ExpiCHO-S™ expression system and then purified. The purified RBD proteins were identified with native gel electrophoresis and Western blot. Then, an equal amount of each RBD protein was used as coating antigen to establish an ELISA for detecting MERS-CoV IgG titer. For comparison, the newly developed ELISA and the commercial MERS-CoV IgG antibody detection kit (Euroimmune with S1 as the coating antigen) were used to measure the MERS-CoV antibody reference panel supplied by World Health Organization (WHO).@*Results@#The purified monomeric and trimeric MERS-CoV RBD were successfully prepared using 293T cells and ExpiCHO-S™ system. RBD antigens of different forms and from different systems could recognize MERS-CoV specific antibody without having any cross reaction with the sera from healthy adults. The in-house RBD-based ELISA had good detection consistency with the Euroimmune commercial kit. The positive samples showed higher and more concentrated values based on the RBD trimer than the monomer.@*Conclusions@#Novel indirect ELISA methods based on the monomeric and trimeric forms of RBD protein were established. The trimetric form-based ELISA achieved higher detection efficiency than the one using the monomer antigen, suggesting that it could be uses as a competent alternative to the commercial kit.
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Objective To investigate the etiological characteristics of common viral respiratory tract infections and to analyze the distribution of human rhinovirus(HRV) serotypes in children with severe acute respiratory tract infection (SARI) in Shanghai. Methods Totally 199 nasopharyngeal aspirate speci-mens were collected from children with SARI in Shanghai from October 2016 to March 2017. A nuclear acid test was performed to detect 15 common respiratory viruses in these specimens. HRV strains were screened out using the primer pairs derived from the 5′UTR of HRV and the serotypes of them were identified based on the VP4-VP2 gene sequencing. Results Among the 199 specimens,HRV-positive specimens accounted for 26.1%,followed by those positive for influenza A(6.5%),adenovirus(6.5%),respiratory syncytial vi-rus(6.5%) and Boca virus(5%). Fifty-two HRV-positive specimens were typed by the VP4-VP2 gene se-quencing with 30 belonging to species A(18 serotypes,predominant serotypes:A21,A12,A38,A78,A88 and A96),seven belonging to species B (five serotypes, predominant serotype: B72) and 15 belonging to species C (nine serotypes,predominant serotypes:C27 and C40). There were two cases of HRV co-infec-tion. Two HRV-positive specimens could not be typed. HRV mixed serotype infections and co-infections of HRV with other viruses were existed. No significant difference in infection rates of different age groups and clinical characteristics was found between HRV-A and HRV-C infection groups. Conclusion HRV-A and HRV-C were the predominant pathogens causing SARI in children in Shanghai. Thirty-two HRV serotypes were detected and the predominant types were A21,A12,A38,A78,A88,A96,B72,C27 and C40.
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Objective@#To detect the expression level of early and late protein of vaccinia virus and to preliminarily explore replication-defective mechanism of highly attenuated NTV strain of vaccinia virus Tiantan.@*Methods@#We constructed prokaryotic expression vector, expressed and purified homologous early protein E3 and late protein A27 closely related to replication and prepared mouse polyclonal antiserum by immunizing mice with homologous proteins. Early and late protein expression levels of NTV were detected.@*Results@#We have expressed and purified vaccinia virus proteins respectively in E. coli expression system and prepared homologous mouse polyclonal antiserum. Early protein E3 and late protein A27 could be highly efficient expression in NTV infected non-permissive Hela cells, while expression of late protein F17 was blocked detected by Western blot.@*Conclusions@#The expression limitation of late protein F17 may be an explanation for the replication-defective mechanism of NTV.