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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 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 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 .