FIG. 6.

Effects of lactose, galactose, and mannose on the release of cytolytic factors by A. castellanii trophozoites. Trophozoites were incubated with complete MEM or complete MEM containing 100 mM mannose, 100 mM lactose, or 100 mM galactose for 48 h at 35°C. Supernatants were collected, centrifuged, filter sterilized, concentrated fourfold, dialyzed against a 10-kDa-cutoff membrane, and added to CHCE cell monolayers. Negative controls consisted of monolayers incubated in medium alone (0% CPE; not shown). CPE was assessed spectrophotometrically 48 h later. Results are expressed as mean ± standard deviation. ∗, the mannose treatment group was significantly different from each of the other groups (P = 0.0001). The lactose and galactose groups were not significantly different from the complete MEM control supernatant (P > 0.05).