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 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 strain, 11 were isolated in China and the other 11 from Tailand, Vietnahailam, Indonesia, India, Philippines and Japan. Results The 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