Static and dynamic assays of cell adhesion relevant to the vasculature

Methods are described for analysing adhesion of isolated cells (such as leucocytes, tumor cells, or precursor cells) to purified adhesion receptors or cultured endothelial cells. "Static" assays (in which cells are allowed to settle on the adhesive substrates) and flow-based assays (in which cells are perfused over the substrates) are compared. Direct observations of the time course of adhesion and migration can be made when purified proteins or endothelial cells are cultured in plates, after cells are allowed to settle onto them for a desired period. In the flow-based assay, cells are perfused through coated glass capillaries or flow channels incorporating coated plates. Again, direct video-microscopic observations are made. In this assay, various stages of capture, immobilisation and migration can be followed. In general, the static systems have higher throughput and greatest ease of use, but yield less-detailed information, while the flow-based assay is most difficult to set up but is most physiologically relevant if one is interested in the dynamics of adhesion in the vasculature.