Seaton D S, Jackson F, Smith W D, Angus K W
Moredun Research Institute, Edinburgh.
Res Vet Sci. 1989 Jan;46(1):22-6.
Infective third stage larvae (L3) of Trichostrongylus vitrinus were radiolabelled with 75 selenium by a method which did not affect their viability. Three groups of six-month-old lambs were infected daily with 1000 L3 for four, eight and 12 weeks, respectively. After each period, one of those groups (n = 5) and a group (n = 4) of worm-free controls were challenged with three consecutive daily doses of 1000 radiolabelled L3, killed 10 days after the first dose, and their worm burdens examined. After four weeks of continuous infection partial immunity to the establishment of challenge L3 was apparent, and by eight and 12 weeks, with the exception of one sheep, there was almost total resistance to incoming worms. Immunity was also expressed as an inhibition of the development of established worms.
用一种不影响其活力的方法，用75硒对玻璃毛圆线虫的感染性第三期幼虫（L3）进行放射性标记。三组6月龄羔羊分别连续4周、8周和12周每天感染1000条L3。在每个时间段后，其中一组（n = 5）和一组（n = 4）未感染蠕虫的对照羊连续3天每天接受1000条放射性标记的L3攻击，在首次给药后10天处死，并检查其虫负荷。连续感染4周后，对攻击L3的建立出现部分免疫，到8周和12周时，除一只羊外，对进入的蠕虫几乎完全产生抗性。免疫还表现为对已建立感染的蠕虫发育的抑制。
