Competition experiments between Ad35K++ and anti-CD46 antibodies. (a) Jurkat cells were stained with anti-CD46-FITC or anti-CD46-phycoerythrin (PE), or with both antibodies added in the different orders, as indicated, and CD46 expression was assessed by flow cytometry. These two clones do not compete with each other. (b) Jurkat cells were first incubated with Ad35K++ (500 ng/nl) for 20 min, washed and then stained with the anti-CD46-FITC, anti-CD46-PE, or indirectly labelled with the MCI20.6 clone followed by anti-mIgG1-FITC. CD46 expression was assessed by flow cytometry. Dotted lines represent isotype controls.