Determination of integrins on cells by cell adhesion to antibodies.

An assay for the determination of relative concentrations of integrins on clonal cultured cells is described. Unpurified monoclonal antibodies to integrin subunits, present in ascites or hybridoma culture media, are immobilized on a plastic surface via goat antibodies to mouse IgG. Cell attachment to the integrin-coated substrate is quantitated after fixation and staining of the cells. The assay is specific and very sensitive; only cells with the relevant integrins attach to antibody-coated substrates and concentrations of antibody as low as 1-10 ng/ml are sufficient. Titrations of the antibodies on the solid phase allow the estimation of the relative amounts of integrins on different cell types. The results with this assay correlate well with results obtained by flow cytometry.