Figure 4.

Linkage between the I domain and activation epitopes in other domains. K562 transfectants stably expressing wild-type αLβ2, or αLβ2 with mutant I domains or activating truncations of the cytoplasmic domains of the αL (αL1090*) or β2 (β702*) subunits were stained with control X63 myeloma IgGl (gray histograms), TS2/4 mAb to αL, TS1/18 mAb to β2 (not shown) in absence of MnCl₂, or activation-dependent mAbs KIM127 or m24 in the presence or absence of 2 mM MnCl₂ (black histograms), followed by immunofluorescence flow cytometry. For each mutant, specific fluorescence intensity was determined as the percentage of the average intensity of TS2/4 and TS1/18 staining, and the mean and difference from the mean in two independent experiments is shown in each panel.