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目的观察日本血吸虫(大陆株)硫氧还蛋白DNA疫苗(pcDNA3-SjcTrx)在小鼠诱导抗血吸虫感染的免疫保护作用。方法制备pcDNA3-SjcTrx重组质粒,将30只雌性C57BL/6小鼠随机分为3组,每组10只:pcDNA3-SjcTrx核酸疫苗免疫组、pcDNA3空质粒对照组和攻击感染对照组。核酸疫苗免疫组每只小鼠经股四头肌注射100μg核酸疫苗,共注射3次,间隔2周。空质粒对照组每只小鼠在相应时间经股四头肌注射100μgpcDNA3空质粒,感染对照组则不注射任何质粒。于末次免疫后3周,每只小鼠经腹部感染(30±1)条日本血吸虫尾蚴。小鼠于攻击感染后42天剖杀,门脉灌注收集成虫,计数成虫数和肝内虫卵数。分别在免疫前、攻击感染前和小鼠剖杀前采血并分离血清,用ELISA检测血清中特异性IgG抗体。另取6只雌性C57BL/6小鼠经股四头肌注射核酸疫苗,分别于注射后24、48小时和72小时取肌肉注射部位局部组织制备冰冻切片,用免疫酶染色试验(IEST)检测注射局部组织抗原的表达情况,以注射pcDNA3空质粒者为对照。结果IEST结果表明该DNA疫苗在小鼠肌肉组织内表达,ELISA检测表明DNA疫苗免疫小鼠后产生明显的抗体(IgG)免疫应答,并诱导出对攻击感染的45.7%的减虫率和41.4%的肝组织减卵率(P<0.05)。结论日本血吸虫(大陆株)硫氧还蛋白DNA疫苗具有较好的免疫原性,在小鼠诱导出明显的免疫保护作用,可作为疫苗候选分子作进一步的研究。
Objective To observe the immunoprotective effect of thioredoxin DNA vaccine (pcDNA3-SjcTrx) of Schistosoma japonicum (Chinese strain) on the induction of anti-schistosome infection in mice. Methods Thirty female C57BL / 6 mice were randomly divided into 3 groups with 10 pcDNA3-SjcTrx recombinant plasmids, pcDNA3-SjcTrx DNA vaccine-immunized group, pcDNA3 empty plasmid control group and challenge infected control group. Nucleic acid vaccine group mice injected via the quadriceps per 100μg nucleic acid vaccine, a total of three injections, two weeks apart. Empty plasmid control group, each mouse at the appropriate time through the quadriceps injection of 100μgpcDNA3 empty plasmid infection control group did not inject any plasmid. Three weeks after the last immunization, each mouse was infected (30 ± 1) with Schistosoma japonicum cercaria via the abdomen. Mice were sacrificed 42 days after challenge challenge and adult animals were collected by portal perfusion to count the number of adults and the number of intrahepatic eggs. Serum samples were collected before immunization, before infection and before the mice were sacrificed. Serum samples were collected for serum-specific IgG detection by ELISA. Six other female C57BL / 6 mice were injected with quadriceps DNA vaccine. The frozen sections were prepared by intramuscular injection at 24, 48 and 72 hours after injection respectively. The IEST test Local tissue antigen expression, injection of pcDNA3 empty plasmid as a control. Results The results of IEST showed that the DNA vaccine was expressed in the muscle tissue of mice. The results of ELISA showed that the immunized mice immunized with DNA vaccine produced significant IgG antibody response and induced a 45.7% reduction in worm burden and 41.4% (P <0.05). Conclusions Thioredoxin DNA vaccine of Schistosoma japonicum (Chinese strain) has good immunogenicity and induces obvious immunoprotection in mice, which can be used as vaccine candidate molecule for further study.