FIG. 1.
Binding and longevity of SEs and TSST-1 on the surface of B cells. (A) SEA, SEB, SED, SEE, or TSST1 (5 μg in 20 μl of RPMI 1640 containing 5% FBS) was added to 2 × 105 paraformaldehyde-fixed LG2 cells, and the toxin was washed away at different times. The amount of binding was measured by using anti-toxin antibody, followed by FITC-labeled secondary antibody and flow cytometry. The data are presented as mean fluorescence intensities. (B) Fixed LG2 cells were incubated as described above with SEA, SEB, SED, SEE, or TSST1 for 45 min and then washed and reincubated in 3 ml of medium containing 10% FBS for different times. Binding of the bacterial SAgs was determined as described above. The data are representative of four different experiments.