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目的对狂犬病病毒CTN-181弱毒株经豚鼠颌下腺传代和空斑纯化而获得的3株弱毒株病毒(CTN-1-3,CTN-1-16和CTN-1-19)进行全面的致病性、免疫性研究和遗传稳定性研究。方法分别对3株病毒用10、14和21日龄小鼠脑内接种,观察小鼠的发病死亡情况进行致病性研究;分别对3株病毒用3周龄小鼠进行肌内免疫和口腔免疫,测定小鼠中和抗体阳转率和中和抗体水平;将3株病毒在乳鼠脑内连续传代或豚鼠颌下腺传代,传代后病毒以小鼠脑内接种观察有无致病性进行遗传稳定性研究。结果在致病性方面:3株病毒均对3周龄小白鼠脑内接种无致病性,其中CTN-1-3和CTN-1-19对14日龄乳鼠约半数存活,而CTN-1-16株则大部分死亡。对10日龄乳鼠只有CTN-1-3株不完全致死。在免疫性方面:3株病毒以≥5.5lg PFU病毒肌内免疫或≥6.5lg PFU口腔免疫的3周龄小鼠,30d后的中和抗体阳转率均为100%,GMT分别为7.0~16.1IU/ml和7.9~39.5IU/ml。在遗传稳定性方面,3株病毒经1~3日龄乳鼠脑内连续传5代或豚鼠颌下腺传1代,传代增殖后的病毒滴度虽高达6.5或8.0lg PFU/ml,对小鼠脑内接种仍保留无致病力的弱毒特性。结论结果表明3株病毒的毒力已高度减弱,免疫效力良好,诱生的抗体水平很高,遗传稳定性十分稳定,是研发兽用狂犬病口服活疫苗和狂犬病暴露后人体免疫用减毒活疫苗的良好候选株。
OBJECTIVE To investigate the comprehensive pathogenicity of three attenuated strains of viruses (CTN-1-3, CTN-1-16 and CTN-1-19) obtained from rabies virus CTN-181 attenuated strain by submandibular gland passaging and plaque purification , Immune research and genetic stability studies. Methods Three viruses were inoculated in the brains of 10, 14 and 21 day old mice, respectively. The pathogenicity of the three viruses was observed. The three strains of mice were immunized intramuscularly and orally Immunization, the mouse neutralization antibody positive rate and neutralizing antibody levels; the three strains of virus in the neonatal rat brain or continuous passage of submandibular gland, the passage of virus in mice intracerebral inoculation to observe whether the pathogenicity of genetic Stability studies. Results In the aspect of pathogenicity, all the three viruses were non-pathogenic to intracerebral inoculation in 3-week-old mice. CTN-1-3 and CTN-1-19 survived about half of 14-day-old neonatal rats, while CTN- Most of the 1-16 strains died. Only CTN-1-3 strains of 10-day-old suckling mice were not completely lethal. Immunocompetence: The three-week-old mice, immunized with ≥5.5lg PFU intramuscularly or ≥6.5lg PFU orally, had 100% positive rate of neutralization antibody after 30 days with GMT of 7.0 ~ 16.1 IU / ml and 7.9-39.5 IU / ml. In the aspect of genetic stability, three viruses were continuously passaged for 5 passages in the brain of 1 to 3 days old rats or submandibular gland of guinea pig for 1 passage. Although the virus titer after passage proliferation was as high as 6.5 or 8.0 lg PFU / ml, Inoculation in the brain still retains virulence characteristics without virulence. Conclusions The results showed that the virulence of the three viruses was highly attenuated, the immune efficacy was good, the induced antibody level was very high, and the genetic stability was very stable. It was the live attenuated vaccine for human immunization with rabies A good candidate strain.