Measurement of Integrin Activation and Conformational Changes on the Cell Surface by Soluble Ligand and Antibody Binding Assays.

Soluble ligand and conformation-dependent antibody binding assay of integrins on the cell surface is an effective approach to evaluate the activation status of integrins in live cells. The ligands or antibodies are usually labeled with biotin or a fluorescent dye and incubated with integrin-expressing cells in suspension. The cell-bound ligands and antibodies are then detected by flow cytometry. Here we describe the detailed protocols of soluble ligand or antibody binding assay for α _IIb β ₃ , α _V β ₃ , α ₅ β ₁ , and α _L β ₂ integrins that are transiently or stably expressed in the model cell lines such as HEK293 or CHO-k1 cells.