Analysis of Integrin-Dependent Rapid Adhesion Under Laminar-Flow Conditions

Adhesion molecules mediate recognition of the blood vessels by circulating leukocytes and support their selective targeting to different organs (1 ). In the vessels, the blood flow imposes peculiar conditions by generating a wall shear stress that opposes leukocyte stable arrest on the endothelium. As the rapidness of integrin activation is mandatory to leukocyte adhesion to the blood vessels, any analysis of adhesion triggering relevant to leukocyte in vivo migration should be performed under flow conditions. Here, a method is illustrated to quantitatively analyze the rapid induction of integrin-dependent lymphocyte adhesion by chemokines under flow conditions. Glass capillary tubes are cocoated with purified ligands for selectins and integrins and with chemokines, thus reconstituting the minimal requirement to support tethering, rolling, and arrest under flow conditions, with a physiologic wall shear stress of 2 dynes/cm² . PNAd, ICAM-1, and the chemokine CCL21 are used as paradigmatic adhesion molecules and physiologic proadhesive agonist. Naive lymphocytes isolated from mouse lymph nodes are used as the cell model. The procedure for quantitative analysis is discussed.