Background:Integrins facilitate binding to the extracellular matrix and other cells.Their subunit β2 is exclusively expressed by leukocytes,binds to the intercellular cell adhesion molecule 1(ICAM-1),and is pivotal f...Background:Integrins facilitate binding to the extracellular matrix and other cells.Their subunit β2 is exclusively expressed by leukocytes,binds to the intercellular cell adhesion molecule 1(ICAM-1),and is pivotal for their recruitment to sites of inflammation such as the atherosclerotic plaque.Methods:To investigate β2-integrin-mediated adhesiveness,a well-established assay for human whole blood was adapted for the analysis of murine T cell subsets.Changes in avidity and affinity were assessed by incubation of murine complexes ICAM-1 in murine whole blood and consecutive stimulation with PMA and Mg^(2+)/EGTA.Underlying signaling pathways in β2-integrin-mediated adhesiveness upon chemokine stimulation with CCL-19 were identified by incubation with reducing substances,and a Ca^(2+)chelator and ROS and Ca^(2+)measurements were carried out.Results:Incubation of murine whole blood with PMA leads to 30-fold and Mg^(2+)/EGTA to 65-fold increase in β2-integrin-mediated adhesiveness of T cells.Specificity of the assay was proven by preincubation of a blocking antibody,leading to a 60%reduction in adhesion capacity.ROS species and Ca^(2+)are crucial for chemokine-mediated β2-integrin activation.In vivo relevance was proven by induction of T cell adhesiveness in whole blood of mice upon myocardial infarction.Conclusions:Our assay allows specific quantification of β2-integrin-mediated affinity and avidity of T cells in whole blood samples.In congruence to human adhesion,these mechanisms are ROS and Ca^(2+)dependent and significantly elevated after myocardial infarction.Our refined and robust assay may be of particular use in phenotyping involved mechanisms in T cell activation in atherosclerotic cardiovascular disease.展开更多
基金DZHK(German Centre for Cardiovascular Research)。
文摘Background:Integrins facilitate binding to the extracellular matrix and other cells.Their subunit β2 is exclusively expressed by leukocytes,binds to the intercellular cell adhesion molecule 1(ICAM-1),and is pivotal for their recruitment to sites of inflammation such as the atherosclerotic plaque.Methods:To investigate β2-integrin-mediated adhesiveness,a well-established assay for human whole blood was adapted for the analysis of murine T cell subsets.Changes in avidity and affinity were assessed by incubation of murine complexes ICAM-1 in murine whole blood and consecutive stimulation with PMA and Mg^(2+)/EGTA.Underlying signaling pathways in β2-integrin-mediated adhesiveness upon chemokine stimulation with CCL-19 were identified by incubation with reducing substances,and a Ca^(2+)chelator and ROS and Ca^(2+)measurements were carried out.Results:Incubation of murine whole blood with PMA leads to 30-fold and Mg^(2+)/EGTA to 65-fold increase in β2-integrin-mediated adhesiveness of T cells.Specificity of the assay was proven by preincubation of a blocking antibody,leading to a 60%reduction in adhesion capacity.ROS species and Ca^(2+)are crucial for chemokine-mediated β2-integrin activation.In vivo relevance was proven by induction of T cell adhesiveness in whole blood of mice upon myocardial infarction.Conclusions:Our assay allows specific quantification of β2-integrin-mediated affinity and avidity of T cells in whole blood samples.In congruence to human adhesion,these mechanisms are ROS and Ca^(2+)dependent and significantly elevated after myocardial infarction.Our refined and robust assay may be of particular use in phenotyping involved mechanisms in T cell activation in atherosclerotic cardiovascular disease.
