Basombrío M A, Nasser J R, Segura M A, Gomez L E
Laboratorio de Patología Experimental, Facultad de Ciencias de la Salud, Universidad Nacional de Salta, Argentina.
J Parasitol. 1997 Dec;83(6):1059-62.
The protective effect of experimental immunization was studied in guinea pigs exposed to vectorial infection by Trypanosoma cruzi. Immunized animals received an inoculum of live-attenuated T. cruzi epimastigotes into a granuloma previously induced by Freund's complete adjuvant in the hind footpad. Seven days later, a delayed-type hypersensitivity reaction was triggered by reinjection of the parasites in the front footpad. The animals were then placed in Triatoma infestans-colonized corrals and exposed to vectorial T. cruzi transmission of the parasite for up to 200 days. The effectiveness of this immunizing protocol was controlled in terms of the number of bites necessary for infection (NBNI) in immunized as compared with control animals. Periodic entomological census allowed for the determination of vector biting and infection rates and the calculation of NBNI. Although this measurement was quite variable between yards, an overall average of 4,973 bites was enough to infect a control guinea pig in 4 separate experiments. The corresponding figure for the experimental group was 21,307 bites, implying that immunized animals could resist a 4.28-fold increase (range: 1.99-8.32) in the number of vector bites before becoming infected.
在暴露于克氏锥虫媒介传播感染的豚鼠中研究了实验性免疫的保护作用。免疫动物在后足垫中预先用弗氏完全佐剂诱导形成肉芽肿，然后接种减毒活克氏锥虫前鞭毛体。7天后，在前足垫再次注射寄生虫引发迟发型超敏反应。然后将动物置于感染有侵扰锥蝽的畜栏中，使其暴露于寄生虫的媒介传播克氏锥虫感染长达200天。根据与对照动物相比免疫动物感染所需的叮咬次数（NBNI）来控制这种免疫方案的有效性。定期进行昆虫学普查可确定媒介叮咬率和感染率，并计算NBNI。尽管不同畜栏之间该测量值变化很大，但在4个独立实验中，平均4973次叮咬足以使对照豚鼠感染。实验组的相应数字为21307次叮咬，这意味着免疫动物在感染前能够抵抗媒介叮咬次数增加4.28倍（范围：1.99 - 8.32）。
