Preparation Of Inactivated Combined Rotavirus And Enterovirus71Vaccine And Evaluation On Efficacy Of Immunization

[Abstract] Rotavirus (Rotavirus, RV) is one of the most important pathogens that cause infantile diarrhea worldwide. Almost all children less than5years of age are infected with RV and it is estimated that about600,000infants worldwide each year are dead due to diarrhea infected by RV. Enterovirus71(Enterovirus71, EV71) is a highly neurotropic enterovirus which infects children under5years of age mainly. Currently known EV71infection can cause hand-foot-and-mouth disease, which can lead some lethal diseases, such as aseptic meningitis and polio-like paralysis and so on. The infection of RV and EV71can be prevented by corresponding vaccines. To date, RV attenuated live vaccines have been sold on the market while EV71inactivated vaccine will be applied soon. The development and application of new vaccines can make more epidemic diseases preventable and controllable and bring us some problems, such as the increasing times of vaccination, the growing economic burden and the reduction of effective prophylactic inoculation and so on. Therefore, the World Health Organization has advocated the development of combined vaccines to reduce the above problems as much as possible.Our study has focused on the basic issue of developing combined vaccines, such as the evaluation of immunogenicity of RV and EV71combined vaccine and the interaction between the two kinds of antigens. ICR mice were vaccinated by monovalent RV or EV71vaccine and RV and EV71vaccine that contained inactivated RV vaccine and inactivated EV71vaccine in different proportions respectively. Neutralization test was used to detect the serum specific antibodies titer of EV71and RV after primary and booster immunization. The results have revealed that the positive rate of serum specific antibodies against EV71has changed from83%-100%to100%in different dose groups and the geometric mean titer has changed from4.0-7.1to25.4-71.8. Meanwhile, the positive rate of serum specific antibodies against RV has changed from50%-67%to100%in different dose groups and the geometric mean titer has changed from2.6to31.2. After primary immunization, the positive rate of specific antibodies against EV71has been slightly higher than the RV. RV-EV71combined vaccine (160/160EU) can induce the strongest antibody responses against RV and EV71. There has been no significant difference between the combined vaccine groups and the monovalent vaccine groups that contain counterpart dose. The research results have indicated that the combined EV71-RV vaccine has been able to induce the humoral immune response against EV71and RV in mice. The level of the antibody response has been related to the ratios of vaccine antigens dose. And there has been no synergistic effect or antagonistic effect between EV71and RV which are the main components of the combined vaccine.