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Antisense inhibition of amoebapore expression in Entamoeba histolytica causes a decrease in amoebic virulence
Author(s) -
Bracha Rivka,
Nuchamowitz Yael,
Leippe Matthias,
Mirelman David
Publication year - 1999
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1999.01607.x
Subject(s) - entamoeba histolytica , biology , virulence , cytolysis , microbiology and biotechnology , gene , transfection , plasmid , gene expression , untranslated region , cytotoxic t cell , virology , messenger rna , in vitro , genetics
Amoebapores have been proposed to be a major pathogenicity factor of the protozoan parasite Entamoeba histolytica , which is responsible for the killing of target cells. These 77‐residue peptides are structural and functional analogues of NK‐lysin and granulysin of porcine and human cytotoxic lymphocytes. Inhibition of amoebapore gene expression in amoebae was obtained following transfection with a hybrid plasmid construct (pAP‐R2) containing the Neo resistance gene and the gene coding for amoebapore A, including its 5′ and 3′ untranslated region (UTR) sequences, in reverse orientation under a promoter (g34) taken from one of the E. histolytica ribosomal protein (RP‐L21) gene copies. Transfectants of virulent E. histolytica strain HM‐1:IMSS, in which the expression of amoebapore was inhibited by ~ 60%, were significantly less pathogenic. Cytopathic and cytolytic activities of viable trophozoites against mammalian nucleated cells, as well as lysis of red blood cells, were markedly inhibited. Moreover, trophozoite extracts of pAP‐R2 transfectant displayed lower pore‐forming activity and were less potent in inhibiting bacterial growth compared with controls. Notably, liver abscess formation in hamsters by the pAP‐R2 transfectant was substantially impaired. These results demonstrate for the first time that amoebapore is one of the pathogenicity factors by which trophozoites of E. histolytica exert their remarkable cytolytic and tissue destructive activity.