Heyworth Martin F
Research Service, Department of Veterans Affairs (VA) Medical Center, Philadelphia, PA 19104, USA - Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Parasite. 2014;21:55. doi: 10.1051/parasite/2014056. Epub 2014 Oct 28.
Immunodeficiency, particularly antibody deficiency, predisposes to increased intensity and persistence of Giardia infections. Giardia-infected immunocompetent hosts produce serum and intestinal antibodies against Giardia trophozoites. The number of Giardia muris trophozoites, in mice with G. muris infection, is reduced by intra-duodenal administration of anti-G. muris antibody. Giardia intestinalis antigens that are recognised by human anti-trophozoite antibodies include variable (variant-specific) and invariant proteins. Nitric oxide (NO) appears to contribute to host clearance of Giardia trophozoites. Arginine is a precursor of NO and is metabolised by Giardia trophozoites, possibly reducing its availability for generation of NO by the host. Work with mice suggests that T lymphocytes and interleukin-6 (IL-6) contribute to clearance of Giardia infection via mechanisms independent of antibodies.
免疫缺陷，尤其是抗体缺陷，会使贾第虫感染的强度增加且持续时间延长。感染贾第虫的免疫功能正常宿主会产生针对贾第虫滋养体的血清和肠道抗体。通过十二指肠内给予抗微小贾第虫抗体，微小贾第虫感染小鼠体内的微小贾第虫滋养体数量会减少。被人类抗滋养体抗体识别的肠贾第虫抗原包括可变（变异特异性）蛋白和不变蛋白。一氧化氮（NO）似乎有助于宿主清除贾第虫滋养体。精氨酸是NO的前体，会被贾第虫滋养体代谢，这可能会减少其被宿主用于生成NO的量。对小鼠的研究表明，T淋巴细胞和白细胞介素-6（IL-6）通过独立于抗体的机制促进贾第虫感染的清除。
