Biotinylation Assay to Determine LFA-1 Recycling in Motile T-Lymphocytes.

The cycles of internalization of the cell surface β2 integrin receptor lymphocyte function-associated antigen 1 (LFA-1) and its re-exposure on the plasma membrane are important for T-cell trafficking. Biotinylation of cells enables to measure surface expression of receptors, and after reducing surface biotin with reducing buffer, enables to measure the internalization of receptors. Here, by using biotin in combination with reducing buffer and recombinant intercellular adhesion molecule-1 (rICAM-1)-coated dishes and subsequent Western immunoblot analysis, we describe how to measure internalization of the LFA-1 receptor and its re-expression back to the cell surface in motile T-lymphocytes.