Fig 4.

Concentration dependence curves for toxin neutralization of protective antigen by the combination of MAbs AVR1046 and 2F9. The concentration of one antibody was varied in the manner indicated on the x axis, while that of the other was held constant. Cell viability is indicated for concentrations of the serially diluted antibody assayed either individually or combined with the other MAb held constant at the concentration indicated. Neutralization obtained with the antibody that was held constant, in the absence of the serially diluted antibody, is indicated on the y axis. Each point corresponds to the mean of the values obtained for three independent sample preparations, with the SD indicated by the error bar. For each independent assay, samples were run on duplicate plates. Each curve is representative of three independent assays each run on different days.