The Immune Effect Of Sequential Immunization Of Poliomyelitis Vaccine And Research The Detection Methods Of Poliovirus

Objective This study is aim to discuss the vaccination effect and detoxification of different sequential immunization of polio vaccine to provide a theoretical basis for develop a reasonable immunization procedures of polio vaccine.Then we compare the different poliovirus detection methods to provide a reference for the selection of reasonable detection methods of poliovirus.Methods A total of 1200 healthy infants aged 2?3 months without a history of polio vaccine in the Guangxi Zhuang Autonomous region were randomly divided into IPV and OPV sequential immunization groups.The seroconversion rate and antibody titer of polio antibodies in serum were detected before immunization and 28 days after basic immunization,and 10%of the subjects in each group were collected before the second dose of vaccination and on the 7th,14th and 28th day after the second and third vaccination.A total of 7 times,all fecal samples were isolated and cultured by L20B and RD cells and the serotypes of poliovirus in cell cultures were identified by neutralization test.The detoxification rates of different types of viruses in different sequential immunization program groups were compared.In the second part,six fecal samples were taken from each group of the above immune program group,and the excretion of poliovirus in fecal supernatant was detected by real-time quantitative PCR,and compared with cell culture method.The intratype identification of poliovirus in cell culture was carried out by ELISA and RT-PCR,respectively,and the results of neutralization test,ELISA and RT-PCR were compared.Results Finally a total of 2062 serum specimen and 806 fecal samples were involved in the statistical analysis.There was no significant difference in the positive rate of poliomyelitis antibody and GMT among the groups before immunization.There was no significant difference in antibody seroconversion rate and GMT between the same immunization procedure in DC group and liquid group after immunization.There was no significant difference in the positive conversion rate of type ? and type ? antibody between 12 groups.The GMT of type ? antibody was higher than that of other groups after immunization with 2IPV+bOPV,and the seroconversion rate of type ? antibody and GMT were significantly increased after immunization with 2 doses of IPV.There was no significant difference in seroconversion rate of poliomyelitis antibodies between cIPV/OPV sequential immunization group and sIPV/OPV sequential immunization group,but the serum antibodies GMT of type ? in sIPV/OPV sequential immunization group was higher than that in cIPV/OPV sequential immunization group,but the serum antibodies GMT of type ? in was lower than that in cIPV/OPV sequential immunization group.After 2 doses of IPV,the GMT of type ? antibody in sIPV/OPV group was significantly increased,And there was no significant difference comparison with cIPV/OPV group.There was no significant difference in type ? antibody GMT between cIPV/OPV group and sIPV/OPV group.In each immunization program group,the detoxification rate reached a peak within 7 days after OPV vaccination and then decreased gradually.The detoxification rate of any type of virus appeared within 3 weeks after the first dose of OPV.The detoxification rate of type ? poliovirus was the highest.And there was no significant difference in the detoxification rate of type ? and type ?poliovirus.The detoxification rate of type ? poliovirus in sIPV+2bOPV group was higher than 2sIPV+bOPV group and 2sIPV+tOPV group;cIPV+2bOPV liquid group was higher than 2cIPV+tOPV group.The positive samples detected by cell culture method can be detected by real-time quantitative PCR,and more positive results can be detected by real-time quantitative PCR.There was no significant difference in the typing of poliovirus in cell culture by neutralization test,ELISA and RT-PCR.Conclusion The basic immunization effect of polio vaccine was affected by different sequential immunization procedures,and the immune effect of two doses of IPV was better than that of one dose of IPV,especially type ?.The sequential immune detoxification of different poliomyelitis was different.The increase of IPV dosage could not significantly reduce the detoxification rate,but could reduce the detoxification time of each type of poliovirus.The detection rate of poliovirus in original fecal samples by real-time quantitative PCR was higher than that by cell culture,but it was unable to judge whether the virus have infectious or not.Therefore,when the number of the sample is large,it can be used to screen out the positive samples by real-time quantitative PCR,and then use the cell culture method to detect.The results of neutralization test,ELISA and RT-PCR are very consistent.The latter two methods can be used instead of the classical neutralization test to identify the type of poliovirus in cell culture.