FIG. 5.

Time course of TcsL extracellular neutralization. In a 96-well plate, CHO cells (5 × 10⁴ cells/well) were treated with 1 pmol of TcdB, TcsL, or acid-pulsed TcsL in a final volume of 100 μl. At the indicated time points, cells were then subjected to neutralizing antiserum or wash treatments. (A) Treated cells were washed vigorously with PBS four times at the indicated time points. (B) Neutralizing antiserum (10 μl) was added to cells at the indicated time points. In both experiments, cells were then observed for 11 h, and CPE were determined by visualization. Curves: solid triangles, TcdB; solid circles, TcsL.