Hillyer G V
Am J Trop Med Hyg. 1985 Nov;34(6):1127-31. doi: 10.4269/ajtmh.1985.34.1127.
The paradox of schistosomiasis is that infection confers immunity to its host, yet immunization with subcellular antigens of the parasite does not, in general, induce protective immunity. Infection or immunization with subcellular antigens of Fasciola hepatica confers high levels of immunity to a challenge infection with another trematode, Schistosoma mansoni. We have isolated by antibody affinity chromatography a Fasciola hepatica/Schistoma mansoni cross-reactive antigen, designated FhSmIII(M), and also have shown that this antigen confers immunity in mice to a challenge infection with S. mansoni. This antigen was compared with a crude F. hepatica worm extract (FhWWE) as to its ability to induce an IgG antibody response in mice, and to determine whether it had a protective effect in mice to a challenge infection with F. hepatica metacercariae. Mice immunized with FhSmIII(M) or FhWWE, and subsequently infected with F. hepatica, developed higher IgG antibody levels to FhSmIII(M), as measured by ELISA, than F. hepatica-infected controls. Mice immunized with FhWWE did not develop significant levels of resistance to challenge with F. hepatica metacercariae. Mice immunized with FhSmIII(M) and infected with F. hepatica metacercariae developed 69%-78% less worms than controls. An F. hepatica/S. mansoni cross-reactive, cross-protective defined immunity antigen confers in mice significant levels of protection to a challenge infection with F. hepatica.
血吸虫病的矛盾之处在于，感染能使宿主产生免疫力，但一般而言，用该寄生虫的亚细胞抗原进行免疫却不能诱导保护性免疫。用肝片吸虫的亚细胞抗原进行感染或免疫，可使机体对另一种吸虫——曼氏血吸虫的攻击感染产生高水平免疫力。我们通过抗体亲和层析法分离出一种肝片吸虫/曼氏血吸虫交叉反应抗原，命名为FhSmIII(M)，并且还证明了这种抗原能使小鼠对曼氏血吸虫的攻击感染产生免疫力。将这种抗原与肝片吸虫虫体粗提物（FhWWE）在诱导小鼠IgG抗体反应的能力方面进行比较，并确定其对小鼠感染肝片吸虫尾蚴的攻击是否具有保护作用。用FhSmIII(M)或FhWWE免疫的小鼠，随后感染肝片吸虫，通过ELISA检测，其针对FhSmIII(M)产生的IgG抗体水平高于感染肝片吸虫的对照小鼠。用FhWWE免疫的小鼠对肝片吸虫尾蚴攻击并未产生显著的抵抗力。用FhSmIII(M)免疫并感染肝片吸虫尾蚴的小鼠，其体内的虫体数量比对照小鼠少69% - 78%。一种肝片吸虫/曼氏血吸虫交叉反应、交叉保护的明确免疫抗原能使小鼠对肝片吸虫的攻击感染产生显著的保护作用。
