IN-VITRO ENTAMOEBA-HISTOLYTICA ADHESION TO HUMAN ENDOTHELIUM - A COMPARISON USING 2 STRAINS OF DIFFERENT VIRULENCE

Extraintestinal dissemination of Entamoeba histolytica is frequently m anifested by the life-threatening amebic liver abscess (ALA). The hepa tic establishment of amebas implies invasion of blood vessels and cont act with the endothelium. By means of a fluorescence-based quantitativ e adhesion assay, we assessed the binding to human endothelial cells o f two E. histolytica strains of different virulence. The highly virule nt strain (L-A) adhered substantially more strongly to unstimulated en dothelium than the nonvirulent one (BG3). Attachment of L-A was increa sed by treatment of endothelial cells with interleukin-1 beta (IL1 bet a). Other proinflammatory cytokines such as interferon-gamma (IFN gamm a) and tumor necrosis factor-alpha (TNF alpha) did not modify the spon taneous adhesion capacity of amebas. For purposes of comparison we als o performed adhesion of the parasites to skin fibroblasts. Adhesion to this cell type was quite low (< 10%). Parasite virulence, differentia l adhesive capacity to endothelial cells, and modulation of the latter phenomenon by proinflammatory factors (IL1 beta) may influence the ev olution and outcome of extraintestinal amebiasis, especially hepatic a bscesses.