Experimental Amebiasis: Immunohistochemical Study of Immune Cell Populations

Abstract

Distribution of immune cell populations was studied in a C3H/HeJ mouse model of intestinal amebiasis from 5 to 60 days post-inoculation with Entamoeba histolytica, using immunoperoxidase techniques. At various time intervals, the ceca from mice were fixed in 10% formalin, dehydrated, embedded and sectioned at 5 microm. Sections were incubated with conjugated peroxidase-labelled antibodies to mouse IgA, IgM, and IgG. Color was developed with 3, 3'-diaminobenzidine tetrahydrochloride (DAB)/H2O2 solution. CD3, CD4, and CD8 cells, as well as neutrophils were detected by reacting with biotin-conjugated anti-mouse CD3, CD4, CD8, and CD11 monoclonal antibodies, followed by their incubation with avidin-peroxidase and color development with DAB/H2O2 solution. Erythrocin B and toluidine blue were used to stain eosinophils and Mast cells, respectively. It was observed that the IgA+ plasma cell was the dominating immune cell present in the mucosa, although eosinophils, neutrophils, CD3+, CD4+, CD8+, IgM+, IgG+ cells and Mast cells were also seen. Results of this study suggest that infiltration of immune cells at the mucosal surface during intestinal amebiasis might be important in the defense against this parasite.

CCR9+ T cells contribute to the resolution of the inflammatory response in a mouse model of intestinal amoebiasis

“…Infiltration of granulocytes is a characteristic of human intestinal lesions (Espinosa-Cantellano and Martinez-Palomo 2000;Ventura-Juarez et al 2007). Also, in murine models of intestinal amoebiasis, an increase in PMN cells, particularly eosinophil, has been reported (Ghosh et al 2000). Nevertheless, controversy exists regarding a specific role for eosinophils in regulating E. histolytica infection (Lopez-Osuna et al 1997).…”

Entamoeba histolytica-secreted cysteine proteases induce IL-8 production in human mast cells via a PAR2-independent mechanism

“…Although neutrophils are the primary target cells of IL-8, IL-8 has other effects on various kinds of cells such as endothelial cells, other granulocytes, macrophages, and mast cells. The infiltration of immune cells including neutrophils, macrophages, and mast cells at the mucosal surface was observed during E. histolytica intestinal amoebiasis, suggesting that these cells might be important in host defense against this parasite [13]. Moreover, an increase in degranulation and disruption of mast cells was reported in E. histolytica –infected mice [16], suggesting that mast cells play a role in E. histolytica –induced tissue inflammation at the inflamed site.…”

The pathogenicity of Entamoeba histolytica is related to the capacity of evading innate immunity

“…Although there are several animal models of intestinal and hepatic amoebiasis (27–32), the surgical procedure used to inoculate amoebas can suppress the innate and acquired immune responses (33–35), leading to an increased susceptibility to infection.…”