Antisense inhibition of expression of cysteine proteinases affects Entamoeba histolytica-induced formation of liver abscess in hamsters

Trophozoites of virulent Entamoeba histolytica transfected with the antisen se gene encoding cysteine proteinase 5 (CP5) have only 10% of the CP activi ty but retain their cytopathic activity on mammalian monolayers. In the pre sent study we found that the transfected trophozoites with low levels of CP activity were incapable of inducing the formation of liver lesions in hams ters.