Host-parasite relationships in amebiasis: conference report.

Entamoeba histolytica has been redescribed as the separate species E. histolytica and Entamoeba dispar. E. dispar is apparently never invasive in humans, while E. histolytica is the etiologic agent of amebic colitis and liver abscess. Virulence factors that may enable E. histolytica to invade include a galactose-specific adhesin, secreted proteases, extracellular matrix receptors, and a cell surface lipophosphoglycan. Progress in vaccine development includes the identification of the cysteine-rich domain of the adhesin and the serine-rich surface protein as protective antigens.