title: Neutral proteinase activities in different strains and clones of Entamoeba histolytica. Correlation with virulence.
abstract: Although several factors are involved in the invasive behavior of E. histolytica, proteinases seem to play a key role. Different proteinases have been found in virulent trophozoites of this parasite. Cytosols of clones A, 32-1 462-1 and L-6 of E. histolytica exhibiting various degrees of virulence were used to study the activity of trypsin-like, plasminogen activator and cathepsin B neutral proteinases with specific synthetic oligopeptides. Cathepsin-B like activity showed the highest values in highly virulent clone A, which is derived from virulent strain HM1:IMSS. On the contrary, non virulent clones had very low activity. Clone L-6, a non virulent subclone of strain HM1:IMSS, retained some cathepsin B-like activity. Trypsin-like and plasminogen activator assays revealed low activity and no differences between virulent and non-virulent clones were found. It is concluded that the Arg-Arg-thiol proteinase (Cathepsin B-like) is a good virulence marker.
authors.affiliation: Unidad de Investigación Clínica en Enfermedades Oncológicas, Instituto Mexicano del Seguro Social, México, DF, México.
authors.forename: L
authors.initials: L
authors.lastname: Benítez-Bribiesca
authors.forename: E
authors.initials: E
authors.lastname: Orozco
authors.forename: G
authors.initials: G
authors.lastname: Martínez
authors.forename: G
authors.initials: G
authors.lastname: García-Rivera
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002401:Cathepsin B; D010450:Endopeptidases / Q000032:analysis*; D004748:Entamoeba histolytica / Q000201:enzymology* / Q000472:pathogenicity; D008969:Molecular Sequence Data; D010960:Plasminogen Activators; D015800:Protozoan Proteins / Q000032:analysis*; D013045:Species Specificity; D013379:Substrate Specificity; D014357:Trypsin; D014774:Virulence
chemical_list: D015800:Protozoan Proteins; D010450:Endopeptidases; D010960:Plasminogen Activators; D014357:Trypsin; D002401:Cathepsin B