Molecular mechanisms of invasion by Entamoeba histolytica.
Amebiasis is the third leading cause of death due to parasitic disease. Adherence to and contact-dependent killing of host cells requires the galactose-inhibitable lectin, a heterodimeric glycoprotein composed of heavy and light subunits. The cysteine-rich extracellular domain of the heavy subunit has identity with beta 1 integrins, complement receptor CD59, and complement components C8 and C9; the light subunit sequence is unlike any other sequenced protein. Monoclonal antibodies to the cysteine-rich domain identify pathogenic-specific domains, have adherence-inhibitory and -enhancing properties, block contact-dependent cytotoxicity, and abrogate complement C5b-9 resistance. The purified lectin has galactose-binding activity and confers C5b-9 resistance to susceptible amebae. The accumulated evidence points to the same cell surface galactose-inhibitable lectin as a mediator of two activities required for invasion: adherence and complement resistance.
Petri
W A
WA
Department of Internal Medicine, University of Virginia, Charlottesville.
Mann
B J
BJ
D000818:Animals; D002448:Cell Adhesion; D004748:Entamoeba histolytica / Q000737:chemistry*; D004749:Entamoebiasis / Q000469:parasitology; D000939:Epitopes; D005690:Galactose / Q000737:chemistry; D006801:Humans; D037102:Lectins / Q000737:chemistry; D008967:Molecular Biology; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics
D000939:Epitopes; D037102:Lectins; D015800:Protozoan Proteins; D005690:Galactose