Latency and heterogeneity ofEntamoeba histolytica hemolysins

Abstract

We have found that the hemolytic potency of P30 — a subcellular fraction that contains most of the hemolytic activity ofEntamoeba histolytica trophozoites — increased up to 100 times by preincubation for 36 h at 36° C. This remarkable increase in potency was due to the in vitro generation of heat-labile as well as heat-stable hemolytic components and could be prevented if P30 was preincubated at 4° C or subjected to either heating at 90° C or to repeated freeze-thawing cycles before preincubation at 36° C. The major hemolytic activity ofE. histolytica thus appears to depend on latent, heat-labile and heat-stable hemolysins that are probably unmasked through the action of endogenous amebal enzymes.