Purification and partial characterization of an hemolytic activity from Entamoeba histolytica

It is generally accepted that hydrolytic and cytolytic amebic components are involved in the pathogenic mechanisms of E. histolytica. We have now identified a lytic activity in two membrane proteins of 23.5 kDa and 25 kDa, which are able to lyse rat erythrocytes. The activity was purified from total homogenates of the virulent strains HM1:IMSS and HM38:IMSS, and the erythrocyte lysis was directly related to protein concentration. The hemolytic activity was heat-sensitive and resistant to reduction by 2-mercaptoethanol. Total amino acid analysis of pure proteins showed a high hydrophobic amino acid content: 36% for 23.5 kDa and 50% for 25 kDa. This hemolytic activity could be related, along with other amebic factors, to tissue damage.