Stress response in Entamoeba histolytica

The heat shock response was studied in the intestinal parasitic protozoan Entamoeba histolytica. Temperature shifts from 37$ sp circ$C to 44$ sp circ$C enhanced the synthesis of five major heat shock (or stress) proteins (HSP) of 100, 50, 42, 37, and 28 kDa. Similarly, exposure of amebae to lymphokine activated macrophages and hydrogen peroxide caused HSP expression. Heat shock caused the reversible inhibition of amebic adherence to Chinese hamster ovary cells and human colonic mucin binding to trophozoites by ${>80 %}$. This was due to a decrease in the surface expression of the Gal/GalNAc adherence lectin and a marked reduction in the lectin mRNA expression. However, the presence of target Chinese hamster ovary cells during recovery at 37$ sp circ$C augmented amebic adherence. These results suggest that E. histolytica trophozoites produce a variety of HSP in response to different stimuli and can modulate the expression of the surface adherence lectin which maybe important in pathogenesis