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Objective:To investigate the humoral immune response to GⅠ.1/GⅡ.4 norovirus (NoV) virus-like particle (VLP) vaccine of different doses in mice.Methods:The GⅠ.1/GⅡ.4 norovirus vaccine was diluted into four different concentrations, containing 50, 25, 8.3 and 2.8 μg/dose antigens, respectively. Aluminum hydroxide adjuvant was used in the control group. Ten 7-week-old BALB/c mice in each group were immunized intraperitoneally with 0.5 ml vaccine or adjuvant on 0 d and 21 d. Blood samples were collected on 35 d and the histoblood group antigen (HBGA) blocking titers of GⅠ.1 and GⅡ.4 antibodies in serum were detected. The differences in antibody levels between the groups were analyzed by SPSS23.0 software.Results:GⅠ.1 and GⅡ.4 HBGA blocking antibodies in 50, 25 and 8.3 μg/dose groups became positive on 35 d after the first dose vaccination. The geometric mean titers (GMT) of GⅠ.1 and GⅡ.4 HBGA blocking antibodies were 488 (95%CI: 249-955) and 489 (95%CI: 302-790) in 50 μg/dose group, 278 (95%CI: 106-728) and 738 (95%CI: 299-1 820) in 25 μg/dose group, 300 (95%CI: 158-570) and 486 (95%CI: 222-1 068) in 8.3 μg/dose group, respectively. The positive rates of GⅠ.1 and GⅡ.4 blocking antibodies in 2.8 μg/dose group were 40% and 70% and the GMT were 23 (95%CI: 10-51) and 85 (95%CI: 24-304), respectively. The GⅠ.1 and GⅡ.4 blocking antibodies in the control group were negative. Statistically significant differences in antibody levels were found between 50, 25, 8.3 μg/dose groups and the control group ( P<0.05), as well as in GⅠ.1 blocking antibodies between 50, 25, 8.3 μg/dose groups and 2.8 μg/dose group ( P<0.05). GⅡ.4 antibody level in 25 μg/dose group was statistically different from that in 2.8 μg/dose group ( P<0.05). Conclusions:GⅠ.1/GⅡ.4 norovirus VLP vaccine at (50-8.3) μg/dose could induce humoral immune response in mice.
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Human rotavirus (RV) is one of the main pathogens that cause non-bacterial acute gastroenteritis diseases globally. Live attenuated vaccine is an effective method to prevent RV infection. In order to improve the safety of RV vaccines, it is a good choice to develop other forms of vaccines other than live virus vaccines to avoid attenuated vaccine strains to restore virulence through back mutation or cause environmental contamination. This article reviews the research of RV virus like particle(VLP) vaccines.
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Objective:To screen the neutralizing epitope of enterovirus 71 (EV71) and determine the specific minimum amino acid sequence that triggers immunity for providing a theoretical basis for the development of synthetic peptide vaccines.Methods:EV71 neutralizing antibody-specific binding clones were panned and sequenced using a phage display random 12-peptide library to obtain the key sequences of neutralizing epitopes. A series of peptides containing the key sequences with N-terminal acetylation (AC) and C-terminal linking to Keyhole limpet hemocyanin (KLH) were synthesized. Serum samples were collected after immunizing mice with the modified peptides. Then the immunogenicity of the peptides and the neutralizing activity of serum samples were analyzed by Western blot, ELISA and neutralization test.Results:After three rounds of panning, cloning and sequencing, KQEKDL was identified as the key motif. The serum samples collected from the mice immunized with the modified series of peptides containing key motifs had different degrees of binding ability to EV71 and VP1 protein. The serum samples of mice immunized the synthetic peptide containing only the minimum key motif (AC-KQEKDL-KLH) had the strongest response to the other three peptides and EV71 and the highest neutralizing titer.Conclusions:The EV71 neutralizing epitope was successfully screened using the phage display random peptide library. The key motif of KQEKDL might be the specific minimum amino acid sequence that triggered the immune system. This study provides a theoretical basis for better understanding the immune response mechanism, evaluating the immunogenicity of the antigens and further research and development of polypeptide vaccines.
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Objective To investigate the epidemiological characteristics of norovirus outbreaks in Shenzhen during 2005 to 2017 in order to provide reference for disease control and prevention. Methods Monitoring data of norovirus outbreaks in Shenzhen from January 1, 2005 to December 31, 2017 were col-lected from Shenzhen Communicable Disease Information System and China Information System for Disease Control and Prevention. Descriptive epidemiological methods were used for data analysis. Results From January 2005 to December 2017, 346 norovirus outbreaks (five or more cases in one community within one week) were reported in Shenzhen, of which 6. 36％ (22/346) were public health emergency events. Fewer outbreaks were reported during 2006 to 2013 and they were mainly caused by GⅡ. 4 genotype, but the num-ber increased sharply since 2014 with 57. 80％ (200/346) occurred in 2016—2017 and the epidemic geno-type changed from GⅡ. 4 to GⅡ. 17 and GⅡ. 2. The outbreaks peaked during November to March (76. 88％, 266/346). There were 63. 87％ (221/346) reported in urban areas, 67. 05％ (232/346) in nurseries and 23. 70％ ( 82/346 ) in primary/middle schools. Among the 22 public health emergency events, 40. 91％ (10/22) were caused by person-to-person contacts, 40. 91％ (10/22) by foodborne trans-mission and 13. 64％ (3/22) by waterborne transmission. Moreover, 75. 80％ (238/314) of the outbreaks in nurseries and primary/middle schools were confined to one classroom and most were due to contact trans-mission. Conclusions Norovirus outbreaks increased obviously since 2014, which might be related to the changes of the predominant genotype from GⅡ. 4 to GⅡ. 17 and GⅡ. 2. It is necessary to strengthen a com-prehensive prevention and control in key units such as nurseries and primary/middle schools in winter and spring.
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Objective To evaluate whether simultaneous vaccination with live attenuated polio vaccine affects the immunogenicity of live attenuated rotavirus ( RV) vaccine. Methods Rotarix produced by GlaxoSmithKline was used as the research object. Two doses of Rotarix were orally administered on day 0 and month 1, and oral live attenuated polio vaccine (OPV) was administered on day 0, month 1 and month 2 according to the national vaccination plan. Healthy infants aged 6 to 16 weeks were randomly divided into two groups:interval vaccination group ( Rotarix and OPV were vaccinated on different days) and simultane-ous vaccination group ( Rotarix and OPV were vaccinated on the same day) . Serum samples were collected on day 0, month 2 and month 12, and serum RV-IgA was measured by enzyme linked immunosorbent assay. Statistical analysis was performed to evaluate whether there were statistical differences in the seroconversion rate and level distribution of RV-IgA between the two groups. Results The seroconversion rate of serum RV-IgA in month 2 was 73. 84％ in the interval vaccination and 63. 95％ in the simultaneous vaccination group, and the difference between them was statistically significant (P<0. 05). The geometric mean concen-trations (GMC) of RV-IgA were 97 EU/ml and 90 EU/ml, respectively (P>0. 05). Compared with the simultaneous vaccination group, the seroconversion rate and GMC of serum RV-IgA in month 12 were higher in the interval vaccination group, and the differences were statistically significant (P<0. 05). Conclusions Simultaneous vaccination with live attenuated polio vaccine would affect the immune response of live attenua-ted rotavirus vaccine, especially the maintenance of RV-IgA antibody level.
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Objective@#To evaluate whether simultaneous vaccination with live attenuated polio vaccine affects the immunogenicity of live attenuated rotavirus (RV) vaccine.@*Methods@#Rotarix produced by GlaxoSmithKline was used as the research object. Two doses of Rotarix were orally administered on day 0 and month 1, and oral live attenuated polio vaccine (OPV) was administered on day 0, month 1 and month 2 according to the national vaccination plan. Healthy infants aged 6 to 16 weeks were randomly divided into two groups: interval vaccination group (Rotarix and OPV were vaccinated on different days) and simultaneous vaccination group (Rotarix and OPV were vaccinated on the same day). Serum samples were collected on day 0, month 2 and month 12, and serum RV-IgA was measured by enzyme linked immunosorbent assay. Statistical analysis was performed to evaluate whether there were statistical differences in the seroconversion rate and level distribution of RV-IgA between the two groups.@*Results@#The seroconversion rate of serum RV-IgA in month 2 was 73.84% in the interval vaccination and 63.95% in the simultaneous vaccination group, and the difference between them was statistically significant (P<0.05). The geometric mean concentrations (GMC) of RV-IgA were 97 EU/ml and 90 EU/ml, respectively (P>0.05). Compared with the simultaneous vaccination group, the seroconversion rate and GMC of serum RV-IgA in month 12 were higher in the interval vaccination group, and the differences were statistically significant (P<0.05).@*Conclusions@#Simultaneous vaccination with live attenuated polio vaccine would affect the immune response of live attenuated rotavirus vaccine, especially the maintenance of RV-IgA antibody level.
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Objective@#To investigate the epidemiological characteristics of norovirus outbreaks in Shenzhen during 2005 to 2017 in order to provide reference for disease control and prevention.@*Methods@#Monitoring data of norovirus outbreaks in Shenzhen from January 1, 2005 to December 31, 2017 were collected from Shenzhen Communicable Disease Information System and China Information System for Disease Control and Prevention. Descriptive epidemiological methods were used for data analysis.@*Results@#From January 2005 to December 2017, 346 norovirus outbreaks (five or more cases in one community within one week) were reported in Shenzhen, of which 6.36% (22/346) were public health emergency events. Fewer outbreaks were reported during 2006 to 2013 and they were mainly caused by GⅡ.4 genotype, but the number increased sharply since 2014 with 57.80% (200/346) occurred in 2016—2017 and the epidemic genotype changed from GⅡ.4 to GⅡ.17 and GⅡ.2. The outbreaks peaked during November to March (76.88%, 266/346). There were 63.87% (221/346) reported in urban areas, 67.05% (232/346) in nurseries and 23.70% (82/346) in primary/middle schools. Among the 22 public health emergency events, 40.91% (10/22) were caused by person-to-person contacts, 40.91% (10/22) by foodborne transmission and 13.64% (3/22) by waterborne transmission. Moreover, 75.80% (238/314) of the outbreaks in nurseries and primary/middle schools were confined to one classroom and most were due to contact transmission.@*Conclusions@#Norovirus outbreaks increased obviously since 2014, which might be related to the changes of the predominant genotype from GⅡ.4 to GⅡ.17 and GⅡ.2. It is necessary to strengthen a comprehensive prevention and control in key units such as nurseries and primary/middle schools in winter and spring.
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Objective To validate a cell infection-based quantitative RT-PCR for evaluating the potency of rotavirus vaccine. Methods According to the ICH ( the International Council for Harmonization) Harmonised Tripartite Guideline, the method was validated for its specificity, accuracy, precision, linearity and robustness. Results The method had good specificity as it could only amplify and detect the corre-sponding type of rotavirus strain. The recovery rates for determining the potency against rotaviruses of G2, G3 and G4 types were 97％ to 108％. The percent coefficient of variation ( CV) of both intra-plate and in-ter-plate precision was≤2. 62％, while the intraday and interday CV was≤1. 76％ and≤2. 27％, respec-tively. The CV between the two experimenters was≤7. 68％. The linearity range of the method was 4. 4-6. 5 UI for G2 type rotavirus, 3. 9-8. 3 UI for G3 type and 3. 5-8. 1 UI for G4 type. Good robustness was observed using the cells of 140 to 160 generations. Conclusions The cell infection-based quantitative RT-PCR was shown to have satisfactory specificity, accuracy, precision, linearity and robustness, suggesting that it was a suitable method for evaluating the potency of multivalent rotavirus live vaccines.
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Objective@#To investigate the genetic characteristics of human norovirus (NoV) among infants under 5 years of age with diarrhea in Chaoyang District, Beijing from 2011 to 2017.@*Methods@#NoV-positive stool samples were collected from 2011 to 2017 in this region. The partial RdRp and VP1 genes were amplified and sequenced. Multi-sequence alignment was performed and phylogenetic tree was constructed using Mega software.@*Results@#A total of 151 samples were sequenced and analyzed. The ratio of male and female was 2.28∶1 with mean age of 1.72 years. Fourteen NoV subtypes were detected, including GII.Pe/GII.4 (47.68%), GII.P12/GII.3 (20.53%), GII.P4/GII.4 (17.22%), GII.P16/GII.2 (3.31%), GII.P12/GII.12 (1.99%), GII.P17/GII.17 (1.99%), GII.P16/GII.13 (1.32%), GII.P7/GII.7 (1.32%), GII.P7/GII.6 (1.32%), GII.P2/GII.2 (0.66%), GII.P21/GII.21 (0.66%), GII.Pg/GII.12 (0.66%), GI.Pa/GI.3 (0.66%) and GI.P6/GI.6 (0.66%).@*Conclusions@#NoV genetic diversity was found among infants under 5 with diarrhea in Chaoyang district, Beijing. The subtypes from surveillance and those from epidemics occurred in chronological order. The surveillance should be strengthened for early detection of new subtype for monitoring the epidemic and vaccine design.
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The challenges posed by norovirus infections to global health are increasing accompa-nied by the rapid rate of the genetic and antigenic evolution of circulating noroviruses. Due to lack of in vitro culture cells and small animal models, norovirus vaccine cannot be prepared by using traditional techniques. With the in-depth understanding and study of norovirus, the subunit vaccines against norovirus infection based on P particles have been developed and presented the characteristics of easily expressed, low cost, high immunogenicity, stable structure and so on. In addition, norovirus P particle has been used as a subvi-ral nanoparticle for vaccine development against other viruses and for antibody production against chronic dis-ease ( Alzheimer′s disease) , which benefits from the accommodation of foreign antigens in the three loops of P particle. In this review, we describe the progresses in the field of P particle related vaccines for providing suggestions about the research and development of multivalent vaccines in China.
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Objective To compare the relationship between the enzyme‐linked immunosorbent assay(ELISA) reagent and West‐ern blot(WB) confirmation reagent for analyzing the quality lever of human T‐cell lymphotropic virus(HTLV) detection reagent . Methods The WB confirmation reagent was used to detect anti‐HTLV antibody in 156 human serum samples of ELISA prelimina‐ry screening positive .The ELISA cut‐off value(optimal value) was selected by using the two‐graph receiver operating characteristics (TG‐ROC) analytical method .The two‐by‐two table analysis was constructed to analyze the consistency of results detected by the two methods ,moreover the McNemar test was used to evaluate the consistency of detection results .The quality level of HTLV de‐tection reagent was comprehensively evaluated .Results Among 156 serum samples of ELISA preliminary screening positive ,only 40 samples were positive by the WB confirmation ,and other 116 samples were negative .The sensitivity and specificity of ELISA de‐tection reagent obtained by TG‐ROC analysis were 97 .5% and 45 .7% respectively ,the TG‐ROC test also indicated that the detec‐tion results had significant difference between ELISA and WB(P<0 .05) .By adjusting the cut‐off value ,the sensitivity and specific‐ity of ELISA were increased to 88 .8% (parametric method) .In the comparison of the parametric method and the non‐parametric method ,the obtained areas under the curve(AUC) was 0 .923 5(parametric method) ,their results were basically consistent .Conclu‐sion Although above results indicate that the detection results of ELISA reagent are different from those of WB ,but adjusting the cut off value can increase its sensitivity and specificity ,thus increases the reliability of diagnosis result .