Entamoeba histolytica: collagenolytic activity and virulence
Related Experiment Videos
Abstract:
Several axenic strains of pathogenic and nonpathogenic Entamoeba histolytica were tested for their capacity to digest native radioactive type I collagen gels and to produce liver abscesses when injected into the liver of newborn hamsters. The results demonstrate that the pathogenic strains of amebas (HM1:IMSS, HM3:IMSS, HM38:IMSS and HK9) have a collagenolytic activity that closely correlates with their in vivo capacity to produce liver lesions. The nonpathogenic isolate (Laredo) did not show collagenolytic activity and failed to produce lesions in the liver of newborn hamsters. The results also demonstrate that type I collagen obtained from rodents and cats is degraded less by amebic collagenase than is bovine collagen, which is similar to human collagen. These findings suggest that species susceptibility to invasive infection may depend, among other factors, on the characteristics of the extracellular components of host tissues.
Insights
Pathogenic Entamoeba histolytica strains digest collagen and cause liver abscesses in hamsters. Nonpathogenic strains lack collagenase activity and do not cause lesions, suggesting collagen
Area of Science:
- Parasitology
- Molecular Biology
- Infectious Diseases
Background:
- Entamoeba histolytica is a protozoan parasite causing amebiasis.
- The parasite's ability to invade host tissues and cause disease, particularly liver abscesses, is not fully understood.
- Extracellular matrix components like collagen may play a role in parasitic invasion.
Purpose of the Study:
- To investigate the collagenolytic activity of pathogenic and nonpathogenic Entamoeba histolytica strains.
- To correlate collagen digestion with the ability to induce liver abscesses in vivo.
- To examine the susceptibility of different collagen types to amebic collagenase.
Main Methods:
- Axenic cultivation of Entamoeba histolytica strains.
- Assay of collagenolytic activity using radioactive type I collagen gels.
- Induction of liver abscesses by injecting amebas into newborn hamster livers.
Main Results:
- Pathogenic Entamoeba histolytica strains (HM1, HM3, HM38, HK9) exhibited significant collagenolytic activity.
- This collagenolytic activity correlated directly with the capacity to produce liver lesions in hamsters.
- The nonpathogenic Laredo strain lacked collagenase activity and failed to induce liver lesions.
- Amebic collagenase degraded bovine and human collagen more effectively than rodent or feline collagen.
Conclusions:
- Collagenolytic activity is a key virulence factor for Entamoeba histolytica.
- The susceptibility of host tissues to invasive amebiasis may depend on the specific characteristics of their extracellular matrix components.
- These findings provide insights into the mechanisms of tissue invasion and host-parasite interactions in amebiasis.