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J Infect Dis. 1985 Sep;152(3):542-9.

Effect of antagonists of calcium and phospholipase A on the cytopathogenicity of Entamoeba histolytica.

Abstract

The in vitro mechanisms by which Entamoeba histolytica trophozoites lyse target Chinese hamster ovary (CHO) cells were examined. Calcium chelators ethylenediaminetetraacetate and ethyleneglycol bis (beta-aminoethyl ether)-N,N'-tetraacetate (10 mM) inhibited amebic cytolysis of target CHO cells (P less than .01). A putative antagonist of intracellular calcium flux, 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8; greater than or equal to 250 microM), inhibited amebic adherence and cytolysis (P less than .001). Quinacrine, Rosenthal's inhibitor (dimethyl-dl-2,3-distearoyloxypropyl-2'-hydroxyethyl ammonium acetate), phosphatidylcholine, and hydrocortisone (greater than or equal to 10(-4) M), all pharmacological antagonists of eukaryotic phospholipase A enzymes, inhibited amebic killing of target CHO cells (P less than .001). At 37 C quinacrine and hydrocortisone reduced amebic adherence to CHO cells, whereas Rosenthal's inhibitor and phosphatidylcholine did not. Phosphatidylcholine and TMB-8 demonstrated a synergistic inhibitory effect on amebic killing of target CHO cells (P less than .001). These studies indicate that extracellular calcium ions, amebic intracellular calcium flux, and amebic phospholipase A activity are required for cytolysis of target cells by E. histolytica.

PMID:
2863317
DOI:
10.1093/infdis/152.3.542
[Indexed for MEDLINE]

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