Entamoeba histolytica and E. dispar trophozoites in the liver of hamsters: in vivo binding of antibodies and complement
Entamoeba histolytica and E. dispar trophozoites in the liver of hamsters: in vivo binding of antibodies and complement
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DOI：
10.1186/1756-3305-3-23
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发表时间：
2010-03-26
影响因子：
3.2
通讯作者：
Caliari, Marcelo V.
中科院分区：
文献类型：
--
作者：
Costa, Cassia A. X.;Nunes, Alvaro C.;Caliari, Marcelo V.
背景资料：人体阿米巴病是由寄生在宿主大肠内的原生动物溶组织内阿米巴引起的，在大肠内可产生无症状的定植，直至严重的侵袭性感染伴血液腹泻并扩散至其他器官。肝内阿米巴原虫病是肠外阿米巴病最常见的形式，其致病机制至今仍存在疑问。在这项研究中，我们评估了在原位结合抗体，补体成分C3和C9的滋养体，在仓鼠的肝脏感染E。histolytica或E.差异这些参数与在这些动物中观察到的肝脏病变的范围和滋养体存活率相关。histolytica或E. dispar菌株，并在接种后12、24、48、72、144和192 h进行尸检。免疫组化法检测滋养体抗体、C3和C9结合。结果：在接种阿米巴的动物肝切片中，与E.溶组织原虫滋养体对E.异极滋养体滋养体E. dispar也更频繁地空泡化，并且在病变中观察到高标记的细胞碎片。C_3补体成分的阳性弥散反应在接种E.感染24和72 h后溶组织。C3（+）和C9（+）滋养体在两个感染组动物的血管腔、肉芽肿和坏死区的内部和边缘中检测到。C3（+）和C9（+）滋养体碎片在E. dispar比E.溶组织剂在接种E. dispar.Conclusion:形态学和免疫组化结果表明，抗体和补体能够结合和破坏实验感染仓鼠肝脏中的一些滋养体，可能选择更具抗性的寄生虫，这是由阿米巴原虫的进展负责。结果表明，E.与大肠杆菌相比，溶组织菌在体内逃避免疫反应的能力增强。dispar，虽然它也会导致实验性肝损伤。
Background: Human amoebiasis is caused by the parasitic protozoan Entamoeba histolytica that lives in the large intestine of hosts, where can produce asymptomatic colonization until severe invasive infections with blood diarrhea and spreading to other organs. The amoebic abscesses in liver are the most frequent form of amoebiasis outside intestine and still there are doubts about the pathogenic mechanisms involved in their formation. In this study we evaluated the in situ binding of antibodies, C3 and C9 complement components on trophozoites, in livers of hamsters infected with E. histolytica or E. dispar. These parameters were correlated with the extension of the hepatic lesions observed in these animals and with trophozoites survivor.Methods: Hamsters were inoculated intra-hepatically with 100,000 trophozoites of E. histolytica or E. dispar strain and necropsied 12, 24, 48, 72, 144 and 192 h after inoculation. Antibodies, C3 and C9 binding to trophozoites were detected by immunohistochemistry. The estimation of the necrosis area and the number of labeled trophozoites was performed using digital morphometry analysis.Results: In the liver sections of animals inoculated with the amoebas, the binding of antibodies to E. histolytica trophozoites was significantly lower than to E. dispar trophozoites. Trophozoites of E. dispar were also more frequently vacuolated and high labeled cellular debris observed in the lesions. Positive diffuse reaction to C3 complement component was more intense in livers of animals inoculated with E. histolytica after 24 and 72 h of infection. C3(+) and C9(+) trophozoites were detected in the vascular lumen, granulomas and inside and in the border of necrotic areas of both infected group animals. C3(+) and C9(+) trophozoite debris immunostaining was higher in livers of E. dispar than in livers of E. histolytica. A positive correlation between necrotic areas and number of C9(+) trophozoites was observed in animals inoculated with E. dispar.Conclusion: Morphological and immunohistochemical results suggest that antibodies and complement are able to bind and destroy some trophozoites in the liver of experimentally infected hamsters, perhaps selecting the more resistant parasites which are responsible by progression of amoebic abscesses. The findings indicate that E. histolytica possesses an enhanced ability in vivo to evade the immune responses compared to E. dispar, although it also causes experimental hepatic lesions.