Triton X-100 insolubility of different surface antigens before and after binding of mAbs.

Daudi or EHRB cells were incubated with 10 μg/mL FITC-mAbs for 15 minutes at 37°C, before washing and dividing the sample in half. One half was maintained on ice in PBS (▪), allowing calculation of 100% binding levels, while the other was treated with 0.5% Triton X-100 (labeled Tx-100) for 15 minutes on ice (▩; stained before Triton X-100 lysis). Cells then were washed once, resuspended, and assessed by flow cytometry. To determine levels of constitutively Triton X-100–insoluble antigens, cells were treated with 0.5% Triton X-100 for 15 minutes on ice and washed prior to staining with FITC-mAbs (■; Triton X-100 lysis before staining). Shown are the mean fluorescence intensity (MFI) values for each sample. Error bars show ± SD of triplicate samples.