Comparison of cell toxicity at comparable levels of immunotoxin binding.

<p>Tac-TGN38 and Tac-furin cells were treated with the indicated dose of LMB-2. After a 24 hour incubation with immunotoxin, cells were washed, and the cells remaining in the well were used for <b>A</b>) Hoechst-based cell count assay or <b>B</b>) LDH assay as described in Methods. Panels A and B show the relative cytotoxicity plotted against the amount of LMB-2 adjusted to reflect the different Tac expression levels (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0047320#pone-0047320-g003" target="_blank">Figure 3C</a>) in the cell lines ([LMB-2] × Tac expression). Here the cytotoxicity has been normalized so that a value of 1 represents the maximum killing observed with the highest dose of LMB-2 for each cell line (relative cytotoxicity). The data points represent the cytotoxicity values averaged over several experiments, cell count assay (n = 9), LDH assay (n = 8). The standard error of the mean is shown.