Entamoeba histolytica "toxin": fetuin neutralizable and lectin-like.

Extracts of Entamoeba histolytica produce rounding and agglutination of mammalian cells in tissue culture. This effect is inhibited or reversed by serum, by the serum glycoprotein, fetuin, or by N-acetyl-D-galactosamine. Concanavalin A produces a similar cytotoxic effect that is blocked or reversed by alpha-methyl mannoside. These properties suggest that the amebal "toxin" has a lectin-like activity.