Objective To establish an indirect ELISA method for detection of measles virus antibody based on the nucleoprotein of measles virus expressed in prokaryotic system selected as the coating antigen.Methods The working conditions were screened and optimized to determine the operation process of indirect ELISA.The anti-measles virus IgG antibody in 157 sera of healthy children and mothers of newborn infants was detected and compared with the commercial measles virus ELISA IgG antibody detection kit.Results The result showed that the coefficient of variation of intra and inter assay repeatability of the indirect ELISA was less than 10％.Compared with the result of the commercial kit,the total concordance rate of serum samples was 95.5％,and the sensitivity and specificity were 94.8％ and 98.3％,respectively.There was no significant difference between the two methods (x2 =0.313,P＞0.05;x2 =0.000,P＞ 0.05) in the positive rate of measles virus IgG antibody in 85 healthy children at the age of 0～ 15 years.The level of measles virus antibody detected by ELISA established in this study showed the same increasing and decreasing trend as that detected by the commercial kit in different age groups.The correlation coefficient r of the quantitative result was 0.893 (P＜ 0.001),which showed the quantitative potential of the method.Conclusions The ELISA method established in this study has good stability,high sensitivity and specificity,and there was no significant difference between the detection results of commercial kit and the ELISA method.It can be used for the seroepidemiological investigation of measles virus and the evaluation of antibody level of the population after vaccination.

Objective:To understand the genetic characteristics of subgenus C human adenovirus (HAdV-C) strain isolated in Hunan in 2014.Methods:An HAdV-C strain named Hunan2014-s024 was isolated from throat swab collected from a child with severe acute respiratory infection in Changsha city of Hunan province in 2014. The whole genome sequence (WGS) was obtained by segmented amplification and sequence splicing. Database of HAdV-C was constructed with the strain from this study and the HAdV-C representative strains from GenBank. The whole genome characteristics was analyzed by using bioinformatics software.Results:Strain Hunan2014-s024 has the highest homology with the HAdV-C strain (MK041244-CHN-2006) isolated from stool sample of a healthy child in Shanxi province in 2006, and the genome of strain MK041244-CHN-2006 was used as the backbone, and penton based gene was replaced by gene fragment from MK041246-chn-2012 strain isolated from a child with acute lower respiratory tract infection in Hunan province in 2012.Conclusions:Our result indicated that 2014 Hunan strain(Hunan2014-s024)is a recombinant virus of 2006 Shanxi strain(MK041244-CHN-2006)and 2012 Hunan strain(MK041246-CHN-2012). Due to the change of pathogenicity, it is necessary to strengthen the molecular epidemiological surveillance of HAdV-C to understand its potential disease burden and public health significance.

Objective:To evaluate the effect of synthetic CpG oligodeoxynucleotide (CpG-ODN) as adjuvant on immune response induced by inactivated human adenovirus (HAdV)-55 antigen in BALB/c mice.Methods:HAdV-55 virus QS prototype strain was purified by plaque to construct a seed bank of vaccine candidate strain. The amplified product of vaccine candidate strain was inactivated by 0.05%β-propiolactone, and purified to prepare perfect virus particle antigen. The purified HAdV-55 antigen was mixed with the same volume CPG-ODN and aluminum hydroxide adjuvant in low-dose group (0.2 mg/ml) and high-dose group (1 mg/ml), respectively, and inoculated BALB/c mice after emulsification. Meanwhile, the control group was set with PBS, and the immunization was enhanced once every 21 days. Respectively on primary immune 21 and 35 days after collecting venous blood in mice and separation of serum, serum was collected at the end of the time of separating spleen lymphocytes in mice. The levels of HAdV-55 specific IgG antibody and neutralization antibody in serum of immunized mice were observed by ELISA and micro-neutralization test, and the levels of lymphocytes secreting IL-4 and IFN-γ cytokines were detected by ELISpot.Results:No matter with or without adjuvant, along with the increase of the number of immunization and vaccination dose of inactivated HAdV-55 antigen induced BALB/c mice virus specific IgG antibody was also significantly increased. However, neutralizing antibody can reach detectable level only after enhanced immunity, and the geometric mean titer (GMT) of neutralizing antibody is between 1: 11 and 1: 23. Different adjuvants have significant effects on the immune response of mice. Low dose antigen combined with CPG-ODN and aluminum hydroxide mixed adjuvant can induce higher humoral and cellular immune responses in mice, and the levels of specific IgG antibody and neutralizing antibody are 2.2 and 1.8 times higher than those in the aluminum hydroxide adjuvant group, respectively. The number of lymphocytes secreting IFN-γ was 2.3 times that of the group immunized with aluminum hydroxide adjuvant.Conclusions:The novel CPG-ODN adjuvant significantly increased the immunogenicity of the inactivated HAdV-55 whole virus antigen in BALB/c mice and directed the cellular immune response toward Th1 type.