Objective:To establish and verify an indirect ELISA for quantitative detection of serum antibody against varicella-zoster virus (VZV).Methods:Recombinant VZV glycoprotein E (gE) was diluted with the coating buffer to concentrations of 2, 0.5, and 0.25 μg/ml. HRP-labeled antibody dilutions were 1∶2 000, 1∶5 000, and 1∶10 000. The optimal coating concentration and the optimal working concentration were determined according to the A450/630 value and the P/N ratio (working reference A450/630 value/blank control A450/630 value). According to the indirect ELISA process, an indirect ELISA quantitative detection method for VZV-specific antibody was established. The linear range, accuracy, and precision of the method were verified. The titers of VZV-specific IgG antibody in 32 serum samples were detected by the established method, fluorescent antibody to membrane antigen (FAMA) test, and commercially available VZV quantitative ELISA kit, and the results of the three methods were compared. Results:The optimal coating concentration was 0.25 μg/ml and the optimal working concentration of HRP-labeled antibody was 1∶10 000. The linear range of the standard curve was 0.015 7-1 mIU/ml; the recovery rate was 95.32%-110.99%, and the coefficient of variation (CV) values for repeatability and the intermediate precision were both less than 10%. The results of the established indirect ELISA were well correlated with the results of FAMA test and commercial ELISA kit (indirect ELISA & FAMA: the correlation coefficient was 0.886 4, indirect ELISA & commercially ELISA kit: the correlation coefficient was 0.806 6).Conclusions:The established indirect ELISA method for serum anti-VZV antibody detection has good accuracy and precision, and shows a good correlation with FAMA test and commercial VZV ELISA kit.

Objective:To establish and verify an indirect ELISA for quantitative detection of serum antibody against varicella-zoster virus (VZV).Methods:Recombinant VZV glycoprotein E (gE) was diluted with the coating buffer to concentrations of 2, 0.5, and 0.25 μg/ml. HRP-labeled antibody dilutions were 1∶2 000, 1∶5 000, and 1∶10 000. The optimal coating concentration and the optimal working concentration were determined according to the A450/630 value and the P/N ratio (working reference A450/630 value/blank control A450/630 value). According to the indirect ELISA process, an indirect ELISA quantitative detection method for VZV-specific antibody was established. The linear range, accuracy, and precision of the method were verified. The titers of VZV-specific IgG antibody in 32 serum samples were detected by the established method, fluorescent antibody to membrane antigen (FAMA) test, and commercially available VZV quantitative ELISA kit, and the results of the three methods were compared. Results:The optimal coating concentration was 0.25 μg/ml and the optimal working concentration of HRP-labeled antibody was 1∶10 000. The linear range of the standard curve was 0.015 7-1 mIU/ml; the recovery rate was 95.32%-110.99%, and the coefficient of variation (CV) values for repeatability and the intermediate precision were both less than 10%. The results of the established indirect ELISA were well correlated with the results of FAMA test and commercial ELISA kit (indirect ELISA & FAMA: the correlation coefficient was 0.886 4, indirect ELISA & commercially ELISA kit: the correlation coefficient was 0.806 6).Conclusions:The established indirect ELISA method for serum anti-VZV antibody detection has good accuracy and precision, and shows a good correlation with FAMA test and commercial VZV ELISA kit.

Objective: To evaluate the immunogenicity of split influenza H1N1 vaccine formulated with an oil-in-water nano-emulsion adjuvant in aged mice and young mice. Methods: A nano-emulsion adjuvant formulated split influenza H1N1 vaccine was used to immunize aged and young mice through intramuscular injection. Each mouse was immunized with 0.012 μg of hemagglutinin (HA) twice with an interval of 28 d. Hemagglutination inhibition (HI) titers in serum were measured 27 d after first immunization. Serum HI, IgG1 and IgG2a titers were detected 14 d after the last immunization. No adjuvant-formulated vaccine and normal saline (NS) were used to set up control groups. Virus challenge test was carried out using 10 times the median lethal dose (LD₅₀) of A/Puerto Rico/8/34 (H1N1) strain two weeks after the last immunization and the protective effects were assessed through measuring the dynamic changes in body weight and survival rate. Results: Higher levels of serum HI, IgG1 and IgG2a antibodies and higher HI antibody conversion rates were induced in the adjuvant groups, especially in the aged mice group, than in the control groups. Nano-emulsion adjuvant improved the immunogenicity of HA and mouse immunity to A/Puerto Rico/8/34 (H1N1). Conclusions Nano-emulsion adjuvant could enhance the immunogenicity of influenza antigens, especially in aged mice.

Objective To analyze the immunostimulatory effects of cyclic dinucleotides ( CDN) on immune responses to a nasal spray influenza split virus vaccine and to evaluate its potential as a mucosal ad-juvant. Methods A H1N1 influenza split virus vaccine combined with different CDN was used for mouse immunization. Each mouse was intranasally immunized twice with 4. 5μg of hemagglutinin (HA) and 10μg of CDN with an interval of 21 d. Titers of hemagglutination inhibition ( HI) antibodies in serum, secretory IgA ( sIgA) in bronchoalveolar lavage fluid and IgG in serum were detected 21 d after the last immunization. Immunostimulatory activities of different CDN were compared. Effects of cyclic di-GMP ( c-di-GMP) and ch-itosan (CSN) on the immunogenicity of H1N1 and H7N9 influenza split vaccines were analyzed and com-pared. H1N1 influenza split vaccine combined with c-di-GMP or CSN was used to immunize mice. Three weeks after the last immunization, these mice were challenged with 10 times the median lethal dose ( LD50 ) of A/Puerto Rico/8/34 (H1N1) influenza virus. Survival rates of the mice were observed for 14 d. Results All three CDN induced high levels of HI antibodies and IgG in serum and sIgA in BALF. HI antibody sero-conversion rates were also higher than those of the control groups. c-di-GMP was superior to CSN in enhan-cing the immunogenicity of H1N1 and H7N9 antigens as higher titers of HI antibodies in serum and sIgA in BALF were induced. Conclusions CDN could enhance the immunogenicity of influenza antigens with better efficacy than CSN adjuvant.