IL-18对pVAX1/SjRPS4·CB质粒疫苗免疫小鼠抗日本血吸虫感染的免疫调节作用  

The immunomodulatory effects of IL-18 against schistosome infection in mice with pVAX1/SjRPS4·CB plasmid vaccination

作　　者：程红兵 周云飞[1] 张树菊 汪世平 冯其梅 刘益萍 崔国艳 魏红[1,4] 李芬 刘明社[3] CHENG Hong-bing;ZHOU Yun-fei;ZHANG Shu-ju;WANG Shi-ping;FENG Qi-mei;LIU Yi-ping;CUI Guo-yan;WEI Hong;LI Fen;LIU Ming-she(Department of Parasitology,Xiangya Medical School,Central South University,Changsha 410078,China;Department of Microbiology,Changzhi Medical College,Changzhi 046000,China;Department of Parasitology,Changzhi Medical College,Changzhi 046000,China;Department of Infection Control,the Affiliated Heping Hospital of Changzhi Medical College,Changzhi 046000,China)

机构地区：[1]中南大学基础医学院医学寄生虫学系,长沙410078 [2]长治医学院微生物学教研室,长治046000 [3]长治医学院寄生虫学教研室,长治046000 [4]长治医学院附属和平医院感染管理科,长治046000

出　　处：《中国寄生虫学与寄生虫病杂志》2018年第4期325-330,共6页Chinese Journal of Parasitology and Parasitic Diseases

基　　金：国家自然科学基金(No.81672051;No.81271862);长治医学院科研启动基金(普及项目)(No.QDZ201524)~~

摘　　要：目的探讨pVAX1/IL-18联合pVAX1/Sj RPS4·CB质粒疫苗对小鼠抗日本血吸虫感染的免疫调节作用。方法 70只BALB/c雌鼠按随机数字表法均分为生理盐水组(NS组)、pVAX1空质粒组、pVAX1/IL-18组、pVAX1/Sj RPS4·CB组和pVAX1/Sj RPS4·CB+pVAX1/IL-18组等5组(每组14只),每组小鼠在左后腿股四头肌注射相应质粒100μg或等量生理盐水,每隔2周加强免疫1次,共免疫3次。小鼠感染前(免疫后3周)尾尖部取血,ELISA检测小鼠血清特异性抗体Ig G以及抗体亚类Ig G1、Ig G2a水平。同时,各组小鼠经腹部贴片感染日本血吸虫尾蚴,(20±1)条/鼠。感染后8周,门静脉灌注法收集日本血吸虫成虫,计算减虫率;取肝组织,显微镜下计数虫卵数,计算减卵率。无菌取脾脏,称重,计算小鼠脾脏指数,噻唑蓝(MTT)法测脾淋巴细胞体外增殖水平。分别于小鼠感染前(免疫后3周)以及感染后2、4、6、8周尾尖部取血,ELISA检测小鼠血清中γ干扰素(IFN-γ)、白细胞介素4(IL-4)水平。结果5组小鼠免疫后3周,ELISA检测结果显示,pVAX1/Sj RPS4·CB+pVAX1/IL-18组Ig G、Ig G1、Ig G2的吸光度(A450值)分别为1.03±0.17、0.32±0.08、0.78±0.12,Ig G2a/Ig G1比值为2.44,均高于其他4组。pVAX1/Sj RPS4·CB+pVAX1/IL-18组的减虫率、减卵率分别为52.0%、63.2%,均高于其他3组(P<0.05)。脾脏指数结果显示,pVAX1/Sj RPS4·CB+pVAX1/IL-18组小鼠脾脏指数为3.32±0.37,高于其他4组(P<0.05)。MTT法检测结果显示,pVAX1/Sj RPS4·CB+pVAX1/IL-18组淋巴细胞体外增殖水平A570值为4.45±0.34,高于其他4组(P<0.05)。小鼠感染前以及感染后2、4、6、8周,pVAX1/Sj RPS4·CB+pVAX1/IL-18组IFN-γ含量分别为(569.07±21.15)、(560.66±30.84)、(577.46±36.45)、(605.03±36.91)、(636.33±37.35)pg/ml,均高于其他4组(P<0.05);各组IL-4含量在感染前后差异无统计学意义(P>0.05)。结论IL-18可增强pVAX1/Sj RPS4·CB疫苗抗日本血吸虫感染的免疫保护效果,且诱导小鼠产生较高的以Th1为主的�Objective To explore the immunoregulatory effect of pVAX1/IL-18 combined with pVAX1/Sj RPS4·CB vaccine against schistosome infection in mice. Methods Seventy female BALB/c mice were divided into 5 groups： the normal saline（NS） group, pVAX1 plasmid group, pVAX1/IL-18 group, pVAX1/Sj RPS4·CB group and pVAX1/Sj RPS4·CB ＋ pVAX1/IL-18 group. The mice were injected with 100 μg plasmid or an equal volume of NS at the quadriceps femoris of the left hind leg, once every other week, for a total of 3 vaccinations. Three weeks after the final vaccination, blood was collected from the tail, and the levels of IgG, IgG1 and IgG2a were determined by ELISA. The mice were then challenged with 20 ± 1 Schistosoma japonicum cercariae through abdominal patching and sacrificed 8 weeks later. Adult worms of S. japonicum were collected by portal vein perfusion to calculate the worm reduction rate. The liver tissue was collected to calculate the egg reduction rate in hepatic tissues under a microscope. Moreover, spleen was collected at a sterile condition, weighed, and the mouse spleen index was calculated. The splenic lymphocyte proliferation level in vitro was determined using MTT assay. Blood was collected from the tail before infection（at 3 weeks after the final vaccination） and at 2, 4, 6, and 8 weeks after infection, to assess the serum levels of IFN-γ and IL-4 by ELISA. Results At 3 weeks after the final vaccination, the A450 values of IgG, IgG1 and IgG2 in the pVAX1/SjRPS4·CB ＋ pVAX1/IL-18 group were 1.03 ± 0.17, 0.32 ± 0.08, and 0.78 ± 0.12,respectively, and the IgG2a/IgG1 ratio was 2.44, all of which were significantly higher than those in the other 4 groups.The worm reduction rate and the egg decrease rate in the pVAX1/Sj RPS4·CB ＋ pVAX1/IL-18 group were 52.0% and63.2%, respectively, both significantly higher than those in the other 3 groups（P〈0.05）. The spleen index in the pVAX1/Sj RPS4·CB ＋ pVAX1/IL-18 group（3.32 ± 0.37） was also significantly higher than those in the other 4 groups（

关 键 词：日本血吸虫 白细胞介素-18 pVAX/SjRPS4·CB 疫苗 

分 类 号：R383.24[医药卫生—医学寄生虫学]