To detect retrospectively the phenotype and stability of the E-protein gene in Japanese Encephalitis （JE） virus strain SA14-14-2 used in the live-attenuated JE vaccine prepears, the viral titer was titrated by plaqu...To detect retrospectively the phenotype and stability of the E-protein gene in Japanese Encephalitis （JE） virus strain SA14-14-2 used in the live-attenuated JE vaccine prepears, the viral titer was titrated by plaque formation in BHK-21 cell cultures, and the neuro-virulence of viruses was assayed in mice with body weight of 12-14 g by intracerebral inoculation. Meanwhile, the total RNA of virus gene was extracted and amplified by RT-PCR with the designed primers, and then it was purified and cloned to the expression vector pGEM-T. The recombinant plasmid was purified and sequenced. It was found that the loss of viral titer of vaccines stored in -20℃ for longer than 10 years was less than 0.5 Lg PFU/ml. No mice inoculated intracerebrally showed signs of illness or even death. The size of plagues of the vaccine virus remained to be small, and the E genes of primary virus seed SA14-14-2 and the vaccines prepared at different years （1987-2001） were unchanged, in- cluding the 8 critical amino acid sites which were different from the parent wild virus strain SA14 and the related neuro-virulence. These results indicate that the genotypic and biological characteristics of the attenuated JE virus strain SA14-14-2 and its vaccines sion noted. prepared are quite stable without any reversion noted.展开更多
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 ...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 mav have effective protection against in Asian JE affected countries.展开更多
文摘To detect retrospectively the phenotype and stability of the E-protein gene in Japanese Encephalitis （JE） virus strain SA14-14-2 used in the live-attenuated JE vaccine prepears, the viral titer was titrated by plaque formation in BHK-21 cell cultures, and the neuro-virulence of viruses was assayed in mice with body weight of 12-14 g by intracerebral inoculation. Meanwhile, the total RNA of virus gene was extracted and amplified by RT-PCR with the designed primers, and then it was purified and cloned to the expression vector pGEM-T. The recombinant plasmid was purified and sequenced. It was found that the loss of viral titer of vaccines stored in -20℃ for longer than 10 years was less than 0.5 Lg PFU/ml. No mice inoculated intracerebrally showed signs of illness or even death. The size of plagues of the vaccine virus remained to be small, and the E genes of primary virus seed SA14-14-2 and the vaccines prepared at different years （1987-2001） were unchanged, in- cluding the 8 critical amino acid sites which were different from the parent wild virus strain SA14 and the related neuro-virulence. These results indicate that the genotypic and biological characteristics of the attenuated JE virus strain SA14-14-2 and its vaccines sion noted. prepared are quite stable without any reversion noted.
文摘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 mav have effective protection against in Asian JE affected countries.
