Figure 3.

TcdB with an N-terminal AGT-tag retains cytotoxic potency. (a) AGT-TcdB potency as a function of protein concentration. Vero cells were treated with serial dilutions of TcdB and AGT-TcdB ± autobiotinylation. The dilution series started at 100 ng/mL and continued with fivefold serial dilutions. The % cell rounding was assessed after 24 hr for each concentration tested. (b) AGT-TcdB potency as a function of time after exposure. Vero cells were exposed to 0.8 ng/mL of TcdB or AGT-TcdB, and the % cell rounding was assessed hourly for five hours and then after 24 hr. The data shown in both (a) and (b) are representative of 3 independent experiments.