Protection of SA14-14-2 live attenuated Japanese encephalitis vaccine against the wild-type JE viruses.

OBJECTIVE

To explore on the immunity of live attenuated Japanese Encephalitis (JE) vaccine (SA14-14-2) to different wild JE virus (JEV) strains.

METHODS

The neutralizing effect of the vaccine against different wild JE virus strains was detected by plaque reduction neutralization test (PRNT), and the immunogenicity was studied on mice by vaccination -challenge protection test. In the PRNT, pooled sera from vaccinated human were tested against 10 strains of JEV, one isolated in Taiwan and 9 from other Asian countries. In the vaccination challenge test, mice received one dose of the live vaccine subcutaneously and were challenged intraperitoneally 14 days later against 22 JEV virus strains, 11 were isolated in China and the other 11 from Tailand, Vietnahailam, Indonesia, India, Philippines and Japan.

RESULTS

The protection rates to all the 22 challenge virus were 90% - 100% when 340 PFU/0.1 ml vaccinate virus was administered. The neutralizing effect showed that all the JEV isolates many have neutralized by the sera.

CONCLUSION

SA14-14-2 live attenuated prepared with strain SA14-14-2 is broadly immunogenic and may have effective protection against in Asian JE affected countries.