Smith M A, Clegg J A
Parasitology. 1979 Jun;78(3):311-21. doi: 10.1017/s0031182000051179.
Very variable levels of immunity to a second infection with Schistosoma mansoni were recorded in 7 strains of mice, 12--15 weeks following a small primary infection. When 2 or more strains of mice were assayed at the same time, less variation occurred within the experiment than between different experiments. This evidence suggested variation between pools of cercariae as the main cause of variability in immunity. In direct experiments in one strain of mouse, 2 different pools of cercariae stimulated widely different levels of immunity to the same challenge. Conversely, challenge infections drawn from different pools showed different susceptibility to immunity stimulated by the same primary infection. Individual clones of cercariae, from snails infected with single miracidia, showed a high level of susceptibility to immunity stimulated by a small bisexual infection, or were not susceptible at all. Antigenic polymorphism is the most likely explanation for the differences observed between clones of cercariae. However, indirect immunofluorescence showed the presence of at least 1 common antigen on the surface of schistosomula derived from different clones of cercariae and clone-specific antigens have not been detected.
在7个品系的小鼠中，在一次小剂量初次感染后12至15周，记录到对曼氏血吸虫二次感染的免疫力水平差异很大。当同时检测2个或更多品系的小鼠时，实验内的差异比不同实验之间的差异小。这一证据表明，尾蚴群体之间的差异是免疫力变异性的主要原因。在对一个品系小鼠进行的直接实验中，2个不同的尾蚴群体对相同攻击刺激出的免疫力水平差异很大。相反，来自不同群体的攻击感染对由相同初次感染刺激出的免疫力表现出不同的敏感性。来自感染单个毛蚴的钉螺的单个尾蚴克隆，对由小剂量两性感染刺激出的免疫力表现出高度敏感性，或者根本不敏感。抗原多态性最有可能解释尾蚴克隆之间观察到的差异。然而，间接免疫荧光显示，来自不同尾蚴克隆的童虫表面至少存在1种共同抗原，且未检测到克隆特异性抗原。
