Ljungström I, Holmgren J, Svennerholm A M, Ferrante A
Infect Immun. 1985 Oct;50(1):243-9. doi: 10.1128/iai.50.1.243-249.1985.
The effect of Giardia muris infection on the diarrheal response and gut mucosal antibody response to cholera toxin was examined in mice. The results obtained showed that the fluid accumulation in intestinal loops exposed to cholera toxin was increased in mice infected with a low number (5 X 10(4) ) of G. muris cysts compared with the response in noninfected mice. This effect was associated with a marked reduction in absorption of oral rehydration fluid from the intestine. In contrast, mice infected with a high dose (2 X 10(5) ) of cysts showed a marked decrease in fluid accumulation in response to the toxin. This decrease might be related to the finding that both G. muris and Giardia lamblia trophozoites can bind significant amounts of cholera toxin. Evidence is presented which suggests that the gut mucosal antibody response, mainly immunoglobulin A but also immunoglobulin G, to an immunization course with perorally administered cholera toxin was depressed in mice infected with G. muris. The reduction in antibody levels was particularly evident when the primary immunization was made very early after infection. The serum antitoxin antibodies to the oral immunization with cholera toxin were, however, not affected. Likewise, the delayed-type hypersensitivity response against sheep erythrocytes in animals primed subcutaneously with sheep erythrocytes was not modified during the course of G. muris infection.
在小鼠中研究了鼠贾第虫感染对腹泻反应及肠道黏膜对霍乱毒素抗体反应的影响。所得结果表明，与未感染小鼠相比，感染少量（5×10⁴）鼠贾第虫包囊的小鼠，暴露于霍乱毒素的肠袢中液体蓄积增加。这种效应与肠道对口服补液的吸收显著减少有关。相反，感染高剂量（2×10⁵）包囊的小鼠对毒素的反应中液体蓄积显著减少。这种减少可能与鼠贾第虫和蓝氏贾第鞭毛虫滋养体均可结合大量霍乱毒素这一发现有关。有证据表明，感染鼠贾第虫的小鼠对经口给予霍乱毒素的免疫过程的肠道黏膜抗体反应（主要是免疫球蛋白A，但也有免疫球蛋白G）受到抑制。当在感染后很早进行初次免疫时，抗体水平的降低尤为明显。然而，经口免疫霍乱毒素后的血清抗毒素抗体未受影响。同样，用绵羊红细胞皮下致敏的动物在鼠贾第虫感染过程中，对绵羊红细胞的迟发型超敏反应也未改变。
