Riggs M W, Perryman L E
Infect Immun. 1987 Sep;55(9):2081-7. doi: 10.1128/iai.55.9.2081-2087.1987.
Cryptosporidiosis, a diarrheal disease of calves and humans caused by the coccidian parasite Cryptosporidium parvum, is terminated in hosts with normal immune systems. To assess the mechanisms of immunity in cryptosporidiosis, it is necessary to isolate and quantitate sporozoites, the infective stage of Cryptosporidium spp. Here we report the (i) separation of infective C. parvum oocysts from calf feces by ether extraction, sieving, and hypochlorite treatment; (ii) separation of viable C. parvum sporozoites from intact and excysted oocysts by anion-exchange chromatography; and (iii) quantitation of sporozoite infectivity in vivo by direct intraintestinal injection of isolated sporozoites in 7-day-old BALB/c mice. When isolated sporozoites were incubated with heat-inactivated immune bovine serum, 25 times the 50% infective dose for 7-day-old mice was completely neutralized. Sporozoites incubated with preimmune bovine serum were infectious for 7-day-old mice.
隐孢子虫病是由球虫寄生虫微小隐孢子虫引起的犊牛和人类的腹泻病，在免疫系统正常的宿主体内会自行终止。为了评估隐孢子虫病的免疫机制，有必要分离并定量隐孢子虫属的感染阶段——子孢子。在此，我们报告了：（i）通过乙醚萃取、筛分和次氯酸盐处理从小牛粪便中分离感染性微小隐孢子虫卵囊；（ii）通过阴离子交换色谱法从完整和脱囊的卵囊中分离活的微小隐孢子虫子孢子；（iii）通过将分离的子孢子直接经肠内注射到7日龄BALB/c小鼠体内来定量子孢子在体内的感染性。当分离的子孢子与热灭活的免疫牛血清孵育时，7日龄小鼠50%感染剂量的25倍被完全中和。与免疫前牛血清孵育的子孢子对7日龄小鼠具有感染性。
