Figure 4.

Effects of amiloride, filipin, and chlorpromazine on CNF1-induced multinucleation of HEp-2 cells. Cells grown in 24-well plates were intoxicated with 10⁻¹⁰ M CNF1 in the presence or absence of the following drugs: filipin, 1.5 μM; chlorpromazine, 10 μg/ml, and amiloride, 1 μM. Cells were washed briefly in HEPES-buffered medium and incubated for 1 h with or without each drug before incubation with CNF1. Then cells were incubated with 10⁻¹⁰ M CNF1 still in the presence of the drug. After 90 min cells were washed, and bafilomycin A1 was added to the medium to block further entry of CNF1. Cell multinucleation, induced by the toxin, was recorded 24 h later and expressed as percentage of control without drugs. Effects of chlorpromazine on DT are given as a positive control.