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@#Abstract: Heterologous boost COVID-19 vaccination can solved the problem of decreased efficacy caused by single dose of vaccine. Heterologous booster with adenoviral-vectored COVID-19 vaccine (Ad5-nCoV) following primary immunization with inactivated COVID-19 vaccines is a widely-used vaccination strategy in clinic, while different routes of Ad5-nCoV administration exist and pose a question which route could be more optimal. In this study, we comprehensively evaluated and compared the vaccine immunity induced in mice immunized according to three different vaccination regimens: “3×phosphate buffered solution(3× PBS)”, “2×inactivated vaccine + 1×inactivated vaccine (3×INA)”, “2×inactivated vaccine + 1×Ad5-nCoV (intramuscular)[2×INA+Ad5(im)]”and“2×inactivated vaccine + 1×Ad5-nCoV (intranasal)[2×INA+Ad5(in)]”. We found that heterologous booster with Ad5-nCoV, irrespective of the route of administration, induced significantly higher levels of anti-Spike IgG and subclasses (IgG1and IgG2c), Spike-specific T cells, class-switched Spike+ memory B cells (MBCs) than homologous booster with 3rd dose of inactivated COVID-19 vaccine. Of note, compared with the intramuscular given, intranasal given of Ad5-nCoV as a booster dose clearly induced higher levels of serum and bronchoalveolar bavage fluid anti-spike immunoglobulin A, and moreover, induced stronger infiltration of major innate effector cells like neutrophils, natural killer cells and dendritic cells into the lung tissue, which suggested that mucosal vaccine responses are generated upon intranasal booster with Ad5-nCoV. Altogether, our study analyzed the vaccine immunity induced by different COVID-19 vaccines administered using different regimens, which may guide the clinical use of other types of prophylactic vaccines aiming to mount improved vaccine responses.
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Objective:To compare the immunogenicity of the prefusion (PreF) and postfusion (PostF) conformations of the respiratory syncytial virus (RSV) F protein.Methods:The expression of PreF and PostF recombinant proteins was analyzed by SDS-PAGE and Western blot. The binding affinity between F protein and its specific antibodies was detected by Octet. The binding antibodies and neutralizing antibodies in immune serum were detected after immunizing mice with PreF or PostF recombinant protein.Results:PreF protein was stable in the form of a trimer after modification with higher binding affinity with monoclonal antibodies such as D25, 8897, AM14, Palivizumab and Motavizumab. PostF protein lacked the antigenic site ? and showed a monomer conformation. Besides, it was unable to bind to D25, 8897 and AM14 antibodies. Animal experiments showed that AS01 adjuvant was better than aluminum adjuvant in inducing binding antibodies and neutralizing antibodies against RSV Long strains. The binding antibodies induced by PreF and PostF recombinant proteins had similar binding ability to PreF protein, while the binding antibodies induced by PostF recombinant protein showed stronger binding ability to PostF than to PreF.Conclusions:PreF has more epitopes and the trimer form of PreF recombinant protein after modification is more stable and can induce stronger neutralizing antibodies. Moreover, the immunopotentiating effect of AS01 adjuvant is better than that of aluminum adjuvant. Therefore, stabilization-based trimer structure modification of PreF and the development of adjuvants are crucial for the development of RSV vaccines.
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Objective:To obtain hepatitis B virus capsid-like particles (CLPs) displaying B-cell linear epitopes of SARS-CoV-2 spike protein and evaluate their immunogenicity.Methods:Four recombinant plasmids expressing fusion proteins (M1-HBc, S1-57-HBc, S14P5-HBc and S21P2-HBc) were constructed by separately replacing codon of alanine at position 80 of hepatitis B virus core protein (HBc) with four genes coding for four B-cell linear epitopes (M1, S1-57, S14P5 and S21P2). These four recombinant proteins were expressed in E. coli BL21 Star (DE3) strains. The expression products were identified using SDS-PAGE, Western blot and native agarose gel electrophoresis (NAGE). CLPs were purified by sucrose density gradient ultracentrifugation, verified for antigenicity by Western blot and used to immunize BALB/c mice. Serum antibody titers were detected by ELISA. Results:The recombinant fusion proteins M1-HBc and S1-57-HBc self-assembled into M1-CLP and S1-57-CLP. The titer of antibody against S1-57 polypeptide in S1-57-CLP-immunized mouse serum approached 1∶1 000 000.Conclusions:Hepatitis B virus CLPs displaying SARS-CoV-2 M1 or S1-57 linear epitopes are successfully expressed in a prokaryotic system and purified. S1-57-CLP has good immunogenicity. This study provides a new idea for the development of novel diagnostic reagents and vaccines for SARS-CoV-2.
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@#Objective To compare the immunogenicity of varicella-zoster virus(VZV)Oka-7S strain and VZV Oka strain.Methods Female BALB/c mice were subcutaneously immunized with VZV Oka-7S and Oka strains at high,medium and low doses(1 000,250 and 62.5 PFU/dose)for total two doses at an interval of 14 d,separately,with 12 mice in each group.The VZV-specific humoral immunity was evaluated based on fluorescent antibody to membrane antigen assay(FAMA),and the VZV-specific cellular immunity was evaluated by enzyme-linked immunospot assay(ELISPOT).Results Both VZV Oka-7S and VZV Oka strains induced specific humoral and cellular immune responses,and showed considerable immune effects;The level of anti-VZV specific IgG in serum of mice in Oka-7S-2.2 group increased significantly with the increase of immunization times and immunization doses.Conclusion The VZV Oka-7S strain had comparative immunogenicity with VZV Oka strain.
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@#Objective To evaluate the safety and immunogenicity of domestic inactivated quadrivalent influenza vaccine(QIV)in people over three years old by using Meta-analysis,in order to provide evidence-based basis for formulating QIV immunization strategy in China.Methods Literature was retrieved by PubMed,EMBASE,Cochrane Library,China Biology Medicine disc(CBMd),Wanfang Database and China National Knowledge Infrastructure(CNKI).All the studies were the random control trials for comparing and analyzing the safety and immunogenicity between domestic QIV and inactivated trivalent influenza vaccine(TIV)for people over three years old.Meta-analysis of the included literature data was performed using Stata1 1.0 software.Results A total of four pieces of literature were included.Compared with TIV,the combined effect value risk ratio(RR)of local and systemic reactions in QIV was 1.10(95% CI:0.88-1.38,I~2= 0,P = 0.809)and 0.97(95% CI:0.87-1.09,I~2= 0,P = 0.485),respectively.Compared with TIV,the RR of seroconversion rate(SCR)and seroprotection rate(SPR)of QIV for the same vaccine strains were 0.98-1.06 and 0.98-1.02,respectively,with no significant difference(I~2were 28.8%-89.9% and 0-80.2%,respectively,each P > 0.05);However,there were significant differences between TIV and QIV for the B vaccine strains not included in TIV.The RR of SCR and SPR for B/Victoria were2.88(95% CI:1.75-4.74,I~2= 98.3%,P < 0.001)and 1.64(95% CI:1.16-2.33,I~2= 99.3%,P < 0.001),while for B/Yamagata were 1.89(95% CI:1.57-2.27,I~2= 94.4%,P < 0.001)and 1.15(95% CI:1.04-1.28,I~2= 98.4%,P < 0.001),respectively.Conclusion For people over three years old,domestic QIV not only produced similar safety and immunogenicity levels to TIV,but also had better immune effect against influenza B vaccine strains not included in TIV.
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@#Objective To express glycoprotein H(gH)of pseudorabies virus(PRV)in mammalian cells and detect its immunogenicity.Methods The gH gene fragment of PRV-XiangA strain was amplified by PCR and inserted into mammalian cell expression vector pIRES-neo3 to construct recombinant expression plasmid pIRES-gH,which was transfected to HEK-293F cells and cultured in suspension for 5 d. The cell culture supernatant was identified by Western blot and purified by nickel ion chromatography column. The purified gH was emulsified with ISA 201 VG adjuvant to immunize 8 female ICR mice,and 8 mice in control group were immunized with the same amount of adjuvant,which was strengthened at 5 and 8weeks after the first dose respectively. The blood samples were collected at 4,7 and 10 weeks after the first dose and detected for the titer of specific antibody and neutralizing antibody in serum of mice;The mice were challenged with PRVXiangA strain(1. 5 × 104TCID50)by nasal drops 2 d after the third blood collection,and observed for the morbidity and mortality daily.Results The recombinant expression plasmid pIRES-gH was constructed correctly as identified by sequencing. The gH protein was successfully expressed and modified by glycosylation in mammalian cells with good reactivity,and about 625 μg purified protein was obtained under 100 mL culture volume. After three times of immunization,mice produced high level of specific antibody and showed the effect of neutralizing PRV,and the titer of neutralizing antibody reached 1∶256. In the challenge test,all the mice in control group became ill and died,while half of the mice in gH immunized group did not get sick with a survival rate of 50%.Conclusion PRV gH was successfully expressed in mammalian cells,and its immune protection was confirmed for the first time,which provided experimental basis for the further research and application of gH,and also provided a new idea for the development of PRV subunit vaccine.
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@#Objective To compare the differences of safety and immunogenicity of DTaP-IPV-Hib-HepB hexavaccine,DTaPIPV-Hib pentavaccine plus HepB single vaccine or DTaP-IPV-HepB pentavaccine plus Hib single vaccine,so as to provide a reference for the marketing and use of hexavaccine in China.Methods Randomized controlled trials(RCTs)of DTaP-IPVHib-HepB hexavaccine,DTaP triple vaccine,Hib,IPV and HepB vaccines published at home and abroad were searched.The safety and immunogenicity of the hexavaccine were evaluated by Meta-analysis using Revman 5.4.1 software.Results A total of 7 articles,8 RCTs and 3 429 subjects were included. Meta-analysis of safety showed that there was no significant difference in the incidence of injection site and systemic adverse reactions after vaccination with hexavaccine and pentavaccine plus single vaccine(P > 0. 05)except for induration at the inoculation site and crying. Meta-analysis of immunogenicity showed no significant difference in antibody indexes after vaccination with hexavaccine and pentavaccine plus single vaccine(P > 0. 05).Conclusion The safety and immunogenicity of DTaP-IPV-Hib-HepB hexavaccine in basic immunity was comparable to that of the control vaccine,and might be applied to infants and young children to prevent related diseases. However,due to the limitations of the quantity and quality of included studies,the above conclusions still depend on the further development of larger sample,multicenter and high-quality
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Objective@#To prepare an inactivated hepatitis A vaccine using a attenuated strain of hepatitis A virus (HAV) H2 and to analyze its immunizing dose, so as to provide the reference for development and production of inactivated hepatitis A vaccines.@*Methods@#Human embryonic lung diploid cells (KMB17) were infected with attenuated HAV H2 strain to proliferate the virus, then the cells containing viruses were harvested, extracted and purified. The obtained virus concentrate was prepared into vaccine bulk and test vaccines with 1 280 EU/mL antigen content. Vaccine testing was carried out according to the inactivated hepatitis A vaccine standards specified in the Part Ⅲ of the Pharmacopoeia of the People's Republic of China (2020 edition). A total of 110 mice were randomly divided into 11 groups, including 5 dose groups (80, 160, 320, 640 and 1 280 EU/dose) of the test vaccine and the reference vaccine, as well as the adjuvant control group. Mice were immunized twice by intraperitoneal injection, their serum HAV antibodies were detected, and the geometric mean titer (GMT) and positive conversion rate of antibodies were analyzed to evaluate the immunising dose of the vaccine.@*Results@#The antigen content and viral titer of the virus harvest solution were 5 120 EU/mL and 8.33 lgCCID50/mL, respectively. The removal rate of foreign protein reached 98.05% and the recovery rate of antigen was 66.25%. The test vaccine met the requirements of Part Ⅲ of the Pharmacopoeia of the People's Republic of China (2020 edition). The GMTs of HAV antibodies in the test vaccine and the reference vaccine dose groups after the second immunization were more than twice higher than those after the first immunization. Regardless of primary immunization or secondary immunization, the GMTs (log2) of HAV antibodies in the test vaccine groups with doses of 160 EU/dose and above were higher than those in the 80 EU/dose group (all P<0.05), while there was no statistically significant differences between the dose groups of 160 EU/dose and above (all P>0.05). The antibody positive conversion rate of 160 EU/dose and above of the test vaccine was 100.00% after the secondary immunization.@*Conclusions@#The inactivated hepatitis A vaccine of attenuated H2 strain tested in this study demonstrates strong immunogenicity in mice, suggesting its potential as a candidate vaccine. The preliminary analysis indicates an immunizing dose of 320 EU/dose for children and 640 EU/dose for adults.
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@#Objective To prepare a novel ACYW135 group meningococcal-cross-reacting material 197(CRM197)conjugate vaccine and evaluate its immunogenicity,so as to lay a foundation for the prevention and control of epidemic cerebrospinal meningitis. Methods Group A,C,Y and W135 meningococcal polysaccharide hydroxyl was activated into cyano group with1-cyano-4-dimethylamino pyridinium tetrafluoroborate(CDAP),respectively. Adipic acid dihydrazide(ADH)was used as a linker to connect one end of the activated polysaccharide by cyanate ester to generate polysaccharide-ADH derivative with exposed hydrazide groups. The monovalent conjugate vaccines were obtained through amide bond coupling between 4-（4,6-dimethoxy-1,3,5-triazin-2-yl）-4-methyl morpholinium chloride(DMTMM)and CRM197. Then the monovalent conjugate was mixed with different lyophilized excipients(sucrose solution,lactose solution,and sucrose + mannitol solution)in proportion respectively and lyophilized to prepare three ACYW135-CRM197 meningococcal conjugate vaccines. The male NIH mice were subcutaneously immunized with the vaccines at 0 and 14 d,with 0. 2 mL/mouse,10 mice in each group. At 21 d after the initial immunization,the blood samples were collected from submandibular vein of the mice,and the serum was separated and detected for the specific antibody level by ELISA. Results The test results of A,C,Y and W135-CRM197 monovalent conjugate all met the requirements of the quality standards. ACYW135-CRM197 vaccine product formed obvious precipitation line with each group of polysaccharide antiserum. The average molecular mass was all in the range of 1 680 000-5 230 000.The seroconversion rates of IgG antibodies against A,C,Y,W135 polysaccharide of three ACYW135-CRM197 conjugate vaccines were all 100%. There was no significant difference in polysaccharide antibody level among ACYW135-CRM197(sucrose),ACYW135-CRM197(lactose)and ACYW135-CRM197(sucrose + mannitol)groups(t = 0. 249-1. 157,each P >0. 05). Conclusion In this study,a novel ACYW135-CRM197 conjugate vaccine was prepared and had good immunogenicity in mice.
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ABSTRACT Inactivated COVID-19 vaccines data in immunocompromised individuals are scarce. This trial assessed the immunogenicity of two CoronaVac doses and additional BNT162b2 mRNA vaccine doses in immunocompromised (IC) and immunocompetent (H) individuals. Adults with solid organ transplant (SOT), hematopoietic stem cell transplant, cancer, inborn immunity errors or rheumatic diseases were included in the IC group. Immunocompetent adults were used as control group for comparison. Participants received two CoronaVac doses within a 28-day interval. IC received two additional BNT162b2 doses and H received a third BNT162b2 dose (booster). Blood samples were collected at baseline, 28 days after each dose, pre-booster and at the trial end. We used three serological tests to detect antibodies to SARS-CoV-2 nucleocapsid (N), trimeric spike (S), and receptor binding domain (RBD). Outcomes included seroconversion rates (SCR), geometric mean titers (GMT) and GMT ratio (GMTR). A total of 241 IC and 100 H adults participated in the study. After two CoronaVac doses, IC had lower SCR than H: anti-N, 33.3% vs 79%; anti-S, 33.8% vs 86%, and anti-RBD, 48.5% vs 85%, respectively. IC also showed lower GMT than H: anti-N, 2.3 vs 15.1; anti-S, 58.8 vs 213.2 BAU/mL; and anti-RBD, 22.4 vs 168.0 U/mL, respectively. After the 3rd and 4th BNT162b2 doses, IC had significant anti-S and anti-RBD seroconversion, but still lower than H after the 3rd dose. After boosting, GMT increased in IC, but remained lower than in the H group. CoronaVac two-dose schedule immunogenicity was lower in IC than in H. BNT162b2 heterologous booster enhanced immune response in both groups.