Related Experiment Videos
Entamoeba histolytica: cytopathogenicity and lectin activity of avirulent mutants
Abstract:
Three clones of Entamoeba histolytica (L-6, C93, C919) were isolated by mutagenesis with ethyl methanesulfonate from the axenic strain HM1:IMSS and were studied for adherence, cytolytic, and soluble galactose inhibitable lectin activity. Avirulent clones adhered to and killed fewer Chinese hamster ovary cells than HM1:IMSS (P less than 0.01). However, only C919 was deficient in adherence to red blood cells. Galactose (1.0 g) completely inhibited adherence of all the mutants to Chinese hamster ovary cells; however, adherence to erythrocytes was only partially inhibitable by galactose. Avirulent mutants were more susceptible to being killed by human neutrophils in vitro (P less than 0.01 compared to HM1:IMSS). Soluble protein preparations from all the avirulent mutants were markedly less mitogenic for human lymphocytes and had lower lectin activity for Chinese hamster ovary cells compared to the HM1:IMSS wild type (P less than 0.01 for each activity with each mutant). Indirect immunofluorescence with a monoclonal antibody (F-14) that recognizes the Gal/GalNAc lectin was positive for L-6 and C919. These findings utilizing avirulent mutants of E. histolytica further support a role for the amebic galactose inhibitable lectin in the in vivo pathogenesis of amebiasis.
Insights
Avirulent Entamoeba histolytica mutants exhibited reduced adherence and cytolytic activity. These findings support the role of the galactose inhibitable lectin in amebiasis pathogenesis.
Area of Science:
- Microbiology
- Parasitology
- Molecular Biology
Background:
- Entamoeba histolytica is an enteric protozoan parasite responsible for amoebiasis.
- Virulence factors, including adherence and cytolytic activity, are crucial for E. histolytica pathogenesis.
- The galactose inhibitable lectin is implicated in E. histolytica virulence.
Purpose of the Study:
- To investigate the role of the galactose inhibitable lectin in E. histolytica pathogenesis.
- To characterize the adherence, cytolytic, and lectin activities of E. histolytica mutants.
Main Methods:
- Generation of avirulent Entamoeba histolytica clones (L-6, C93, C919) through ethyl methanesulfonate mutagenesis.
- Assessment of adherence to Chinese hamster ovary cells and erythrocytes.
- Evaluation of cytolytic activity against Chinese hamster ovary cells and susceptibility to neutrophil killing.
- Quantification of soluble galactose inhibitable lectin activity and mitogenicity for human lymphocytes.
- Indirect immunofluorescence using a monoclonal antibody against the Gal/GalNAc lectin.
Main Results:
- Avirulent clones showed significantly reduced adherence and cytolytic activity against Chinese hamster ovary cells compared to the wild-type HM1:IMSS.
- Clone C919 exhibited deficient adherence to red blood cells, while galactose partially inhibited erythrocyte adherence for all mutants.
- Avirulent mutants were more susceptible to neutrophil-mediated killing and displayed lower lectin activity and mitogenicity.
- Indirect immunofluorescence confirmed the presence of the Gal/GalNAc lectin in avirulent mutants L-6 and C919.
Conclusions:
- The study provides further evidence for the involvement of the amebic galactose inhibitable lectin in the in vivo pathogenesis of amebiasis.
- Mutations affecting lectin activity result in decreased virulence of Entamoeba histolytica.
- Characterization of these avirulent mutants aids in understanding the molecular mechanisms of amoebiasis.