Assay of Adhesion Under Shear Stress for the Study of T Lymphocyte-Adhesion Molecule Interactions

Abstract

Overall, T cell adhesion is a critical component of function, contributing to the distinct processes of cellular recruitment to sites of inflammation and interaction with antigen presenting cells (APC) in the formation of immunological synapses. These two contexts of T cell adhesion differ in that T cell-APC interactions can be considered static, while T cell-blood vessel interactions are challenged by the shear stress generated by circulation itself. T cell-APC interactions are classified as static in that the two cellular partners are static relative to each other. Usually, this interaction occurs within the lymph nodes. As a T cell interacts with the blood vessel wall, the cells arrest and must resist the generated shear stress.(1,2) These differences highlight the need to better understand static adhesion and adhesion under flow conditions as two distinct regulatory processes. The regulation of T cell adhesion can be most succinctly described as controlling the affinity state of integrin molecules expressed on the cell surface, and thereby regulating the interaction of integrins with the adhesion molecule ligands expressed on the surface of the interacting cell. Our current understanding of the regulation of integrin affinity states comes from often simplistic in vitro model systems. The assay of adhesion using flow conditions described here allows for the visualization and accurate quantification of T cell-epithelial cell interactions in real time following a stimulus. An adhesion under flow assay can be applied to studies of adhesion signaling within T cells following treatment with inhibitory or stimulatory substances. Additionally, this assay can be expanded beyond T cell signaling to any adhesive leukocyte population and any integrin-adhesion molecule pair.

PLCε1 regulates SDF-1α–induced lymphocyte adhesion and migration to sites of inflammation

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Prognosing a severe course of asthma in children following the study of endothelial function

“…At this stage, the function of the endothelium is actively studied in various pathological conditions, both in children and in adults (22)(23)(24). The regulation of vascular tone is due to the balanced formation and release of vasodilator and vasoconstrictor substances (25). One of the major vascular tone regulators is nitric oxide, which is continuously formed from l-arginine by endothelial NO-synthetase and has a pronounced vasodilating effect.…”

Mechanical shear stress and leukocyte phenotype and function: Implications for ventricular assist device development and use

“…T lymphocytes, the most studied lymphocyte subtype in terms of shear stress, differ fundamentally to neutrophils and monocytes as they crawl against blood flow. 74 Adhesion of T lymphocytes to the blood vessel wall occurs rapidly and firmly -cells must arrest at the endothelium and resist shear stress once tethered, which relies on polarised adhesion. 74 In one study, increasing shear stress from 0.03 to 0.12 Pa decreased the fraction of adherent lymphocytes suggesting disruption of the adhesive mechanism between T lymphocyte and endothelium.…”

“…74 Adhesion of T lymphocytes to the blood vessel wall occurs rapidly and firmly -cells must arrest at the endothelium and resist shear stress once tethered, which relies on polarised adhesion. 74 In one study, increasing shear stress from 0.03 to 0.12 Pa decreased the fraction of adherent lymphocytes suggesting disruption of the adhesive mechanism between T lymphocyte and endothelium. 75 When subjected to significantly higher than physiological shear stress (10-20 Pa) for 10 min, T lymphocytes were no longer able to proliferate on stimulation with the lectin phytohaemagglutinin-P (PHA-P) and IL-2 production was diminished.…”