Susceptibility to Entamoeba histolytica Intestinal Infection Is Related to Reduction in Natural Killer T-Lymphocytes in C57BL/6 Mice

Abstract

Entamoeba histolytica is a protozoan that causes amoebiasis. Recent studies demonstrated that natural killer T lymphocytes (NKT) are critical for preventing the development of amoebic liver abscess. In spite of that, there are only a handful of studies in the area. Herein, we explored the role of NKT cells in E. histolytica infection using C57BL/6 wild-type and CD1−/− mice. Animals were inoculated with E. histolytica and sacrificed 48 hours later to collect caecum samples that were used for quantitative analyses of lesions, trophozoites, NK1.1+ T lymphocytes and expression of the mucus protein MUC-2 by immunohistochemistry technique. Quantitative analyses confirmed that the frequency of NK1.1+ T cells was significantly lower in samples from C57BL/6 CD1−/− mice as compared to their wild type (WT) counterparts. The extension of necrotic mucosa was larger and the number of trophozoites higher in Entamoeba (Eh)-infected CD1−/− mice when compared with Eh-infected WT mice. In mice from both groups, non-infected (CTRL) and Eh-infected CD1−/−, there was a reduction in the thickness of the caecal mucosa and in the MUC-2-stained area in comparison with CTRL- and Eh-WT mice. Our results showed that NKT lymphocytes contribute to resistance against Entamoeba histolytica infection and to the control of inflammation in the colitis induced by infection. The presence of a normal epithelial layer containing appropriate levels of mucus had also a protective role against infection.

Weissella paramesenteroides WpK4 ameliorate the experimental amoebic colitis by increasing the expression of MUC‐2 and the intestinal epithelial regeneration

“…In other words, the augment of mucus, especially of MUC‐2, favours the recomposition of the mucosal epithelial barrier and contributes to the clinical recovery of mice. MUC‐2 is of great importance for the resistance to amoebiasis (Oliveira et al 2012). In this sense, a lower expression of MUC‐2 would increase the susceptibility to infection by Entamoeba trophozoites (Hamano et al 2006), and the absence of MUC‐2 should facilitate the entry of pathogenic micro‐organisms into epithelial cells (Johansson et al 2008).…”

“…For the quantitative analysis of the mucin area, a methodology was used according to Oliveira et al (2012). PAS stained‐histological sections were visualized using the 10x lens for scanning random images through the SDC‐415 Microcamera.…”

“…The quantitative analysis of the expression of MUC‐2, IgA and CDC‐47 was performed according to methods described in Costa et al (2010b) and Oliveira et al (2012). Histological sections submitted for immunohistochemical staining were visualized by the 10x (MUC‐2 and IgA) or 20x (CDC‐47) lens for scanning random images through the Qcolor 3 Microcamera (Olympus, Tokyo, Japan).…”

Helicobacter pylori Containing More Phosphorylation Sites of the CagA Protein Induces Greater Reduction of Gastric Mucins

“…A total area of 9x10 5 µm 2 of the antral mucosa was scanned by a microcamera Q-Color3 (Olympus, Tokyo, Japan) for each animal. The area was calculated with the use of algorithms sequences built in the KS300 software coupled to a Carl Zeiss image analyzer (Oberkochen, Germany) [18]. Through the segmentation of images all brown pixels related to immunohistochemical markers were selected for creation of binary images and the subsequent calculation of the area (μm 2 ).…”

Effects of Invariant NKT Cells on Parasite Infections and Hygiene Hypothesis

“…EhLPPG treatment, similar to α -GalCer application, induced protective IFN- γ but not IL-4 production from iNKT cells and significantly reduced the severity of amebic liver abscess in mice infected with E. histolytica [ 44 ]. By the use of CD1d KO mice, it was found that iNKT cells contributed to resistance against this protozoan and to the control of inflammation in the colitis induced by the infection [ 45 ]. iNKT cells play important roles in the pathogenesis of some other parasitic diseases, as well as of a wide range of microbe infections, as seen in recent nice reviews [ 10 , 46 , 47 ].…”