Primary Evaluation On Immunogenecity Of Enterovirus 71 And Hepatitis A And B Combined Vaccine

Objective To primarily evaluate the interaction of three antigens in enterovirus 71 (EV71) and hepatitis A and B combined vaccine as well as the specific immune response level induced by the vaccine in mice. Methods EV71, HAV and HBV combined vaccine (EV71-HAV-HBV) was formulated by direction adsorption of inactivated EV71, HAV vaccine antigen and HBsAg, at routine dosages, onto aluminum hydroxide adjuvant, with which BALB/c mice were immunized i.m. twice on days 0 and 28 respectively, using HAV-HBV vaccine, HAV-EV71 vaccine, HBV-EV71 vaccine, monovalent EV71, HAV and HB vaccines, adjuvant and PBS (blank) as controls. Serum samples were collected at weeks 2 and 4 after the first dose and weeks 2,4,8,16,28 after the second dose, and determined for anti-HBs and anti-HAV level by ELISA and for neutralizing antibody titer against EV71 by micro-neutralization test. The serum from the mice was collected for analysis in detection assays targeting TNF、IFNγ、IL-5、IL-4、IL-2. These assays were conducted simultaneously using a Th1/Th2 Cytokine Cytometric Bead(CBA) assay kit at week 3,4,5,6,8 after the first dose, the levels of CD3+CD4+T cells and CD3+CD8+T Cells were detected by the Flow Cytometry. The spleens of mice were taken out at weeks 3 and 4 after the first dose and weeks 1,2 and 4 after the second dose, from which mono nuclear cells (MNCs) were isolated and determined for the secretion level of IFNy by enzyme-linked immunospot assay (ELISPOT). Results All the positive conversion rates of anti-HBs and anti-HAV of mice in various vaccine groups reached 100% at week 2 and 4 after the second dose respectively, but not all the positive conversion rates of neutralizing antibody against EV71 of mice in various vaccine groups reached 100%, while there was no seroconversion of antibody in adjuvant and blank control groups. The CD3+, CD4+ results of most group reached high levels at week 4 and then decreased at week 5, while The CD8+ results of most group reached the peak at week 3 and then decreased at week 4. The 5 Cytokine levels of EV71, HAV and HBV combined vaccine groups are higher than other groups which indicated that the reaction to antigens of combined vaccines are faster than other groups. The numbers of spot forming cells (SFCs) which stimulated by HBsAg and EV71 secreting IFNγ in various vaccine groups varied at five different times, and IFNγ secretion levels increased significantly at week 5 and reached the peak value. Both the ELISPOT results in HAV stimulated experiments, adjuvant and blank control groups were negative. Conclusion EV71 and hepatitis A and B combined vaccine at a certain dosage induced high humoral and cellular immune responses in mice, and no interactions were observed between the three vaccine antigens.