狂犬病病毒糖/核蛋白基因疫苗中间试验生物安全评价

目的　本试验应用狂犬病病毒糖/核蛋白“二价”DNA疫苗- pVGN免疫4 0条无狂犬病疫苗免疫史的家犬,共免疫3次。通过观察受试犬的临床表现,监测抗性基因的转移,检测质粒及其主要元件在主要脏器和注射组织的分布、存留及整合,观察主要脏器组织病理学变化,分析疫苗对妊娠母犬及其子代的影响,来评价该疫苗的生物安全性。结果表明,该DNA疫苗可在动物体内诱导良好的体液免疫反应。同时,受试犬未出现任何异常临床表现;DNA疫苗中的卡那霉素抗性基因未在免疫犬肠道正常菌群中发生转移,DNA质粒也未经肠道菌群、尿液和唾液排放到体外;在心、脾、肾和注射部位均能检测到质粒的存在,并分别能存留约18、14 - 18、14和2 6周以上,但质粒DNA未与上述组织的基因组DNA发生整合;在主要代谢器官肝脏中始终未检测到质粒DNA或其主要元件;上述各主要脏器未出现组织病理学变化;对妊娠母犬和其子代无不良影响。说明本狂犬病“二价”DNA疫苗不仅具有良好的免疫原性,而且具有很好的安全性。

Evaluation on the biosafety for the rabies virus glycoprotein/nucleoprotein DNA vaccine in dogs

Forty un-vaccinated dogs were immunized with rabies virus glycoprotein/nucleoprotein bivalent DNA vaccine pVGN for 3 times, and the biosafety was evaluated by means of the observation on the development of immune responses in the immunized dogs, monitoring the transference of the kanamycin-resistance gene, detection of the distributions of plasmid in the main organs and the injected tissues; observations of the pathological changes in the main organs as well as analysis of the influences of vaccine on the pregnant dogs and their puppies. The result showed that this DNA vaccine could induce excellent humoral immune responses in the immunized dogs without any abnormal clinical responses observed. Transference of the kanamycin-resistance gene in the DNA vaccine to the normal intestinal flora did not occur, and this gene was also not excreted into surroundings through intestinal flora, urine and saliva. The plasmid could be detected in heart, kidney and the injected tissues, and persisted in these area for 18, 14～18, 14 and 26 weeks respectively, while it could not be detected in liver. No integration of the plasmid DNA with the genomic DNA in the above-mentioned area was found. Also, there were no histopathological changes observed in the main organs. The vaccine had no influence on the pregnant dogs and their puppies. It indicates that this bivalent DNA vaccine not only possess the satisfied immunogenicity, but also has no problem on biosafety.