日本血吸虫pVAX1/SjRPS4·CB多价疫苗免疫对小鼠肝脏虫卵肉芽肿形成的影响

Effects on the liver egg granuloma formation in mice immunized by pVAX1/SjRPS4·CB vaccine of Schistosoma japonicum

目的观察血吸虫pVAX1/SjRPS4.CB多价疫苗诱导免疫对小鼠肝脏虫卵肉芽肿大小的影响。方法 55只昆明小鼠随机分成5组。PBS对照组、pVAX1空质粒组、pVAX1/SjRPS4单价疫苗组、pVAX1/SjCB单价疫苗组、pVAX1/SjRPS4.CB多价疫苗组,每组小鼠在左后腿股四头肌肌注100μg相应质粒或等量PBS。每隔2周加强免疫1次,共3次。末次免疫后2周经腹部皮肤攻击感染日本血吸虫尾蚴。感染后第6周剖杀小鼠,取出肝脏,常规切片染色,光镜下进行组织学观察及单个虫卵肉芽肿大小的测量。结果与对照组相比,pVAX1/SjRPS4.CB多价疫苗免疫组虫卵肉芽肿平均周长和面积明显减小(P<0.05)。形态学观察免疫小鼠肝脏虫卵肉芽肿周围仅有少量的嗜酸性粒细胞聚集,很少见到胶原纤维。结论 pVAX1/SjRPS4.CB多价疫苗具有明显抑制肝脏血吸虫卵肉芽肿的效果。

To study the effect of pathological changes in Schistosoma japonicum egg granuloma formation in liver of mice immunized with multivalent vaccine pVAX1/SjRPS4·CB,fifty Kunming mice were divided into five groups as PBS control group,pVAX1 empty plasmid group,pVAX1/SjRPS4 monovalent vaccine group,pVAX1/SjCB monovalent vaccine group,and pVAX1/SjRPS4·CB multivalent vaccine group,and each group was immunized with 100 μg plasmid or PBS through musculus quadriceps fexoris of left hind legs for three times with two weeks＇ interval.Two weeks after the final immunization,all mice were challenged with cercariae percutaneously.After six weeks infection,the mice were sacrificed and liver samples from each group were taken for pathological study,and the size of granuloma was measured and the main cell composition was observed under the light microscope.A significant decrease in average perimeter and area of egg granuloma in pVAX1/SjRPS4·CB group was observed as compared with that in the PBS control group（P0.05）.In pVAX1/SjRPS4·CB group,there was few eosinocytes and collagenic fibre in morphology.The result indicated that the pVAX1/SjRPS4·CB multivalent vaccine against Schistosoma japonicum may obviously restrain the egg granulomas of mice in livers.