FIG. 6.
MCF-7 cells were cultured with 10 ng of abrin/ml (a and b) or 100 ng of ricin/ml or 1 μg of A. precatorius agglutinin I (APA-I)/ml (b) in the presence of A-chain-specific MAbs (25 μg/ml) for a period of 8 h. After the treatment, the cells were subjected to 2 h of leucine starvation, followed by [3H]leucine incorporation for 1 h. The total cellular protein was precipitated, and the incorporated radioactivity was measured. Sp2/0 culture supernatant was included as a negative control. The experiment was carried out at least three times. Representative data are presented. DMEM, Dulbecco's modified Eagle's medium.