Abstract:

Objectivem   To compare immunological effect  of different immunization schedules on enterovirus 71(EV71), and choose the best immunization schedule. Methods   EV71 was prepared ,and then the virus was inactivated and titrated.  BALB / c mice were randomly divided into 5 groups of 9.  Groups 1 and 2 were immunized by the inactivated virus, while groups 3 and 4 by the live virus. Group 5 was the control group, immunized by PBS. The immunization interval was two weeks in groups 1,3 and 5, while it was three weeks in groups of 2 and 4. Antibody titers were detected by indirect ELISA after four times of immunization. Results   The antibodies were positive in the four experimental groups (A/A0≥2.1)，while negative in the control group (A/A0＜2.1). The absorbance value of the five groups were 1.0817±0.2897, 1.0296±0.3719, 1.0748±0.3749, 1.4929±0.2159, and 0.1687±0.0218, and the differences were significant by one-way ANOVA (F=23.449，P＜0.05).LSD-t test showed that the antibody titer of group 4 was different from those of groups 1, 2, and 3 (P＜0.05), while no difference was found among groups 1, 2, and 3 (P＞0.05). Conclusion   The antibody titers were  different among these five groups and the highest in group 4.  So the ideal schedule to obtain high titer antiserum is immunization by the live virus at three-week intervals.

Key words: Enterovirus 71; Immunization schedule; Antibody titer