LEUKOCYTE ADHESION

Adhesion of leukocytes is a major event in the induction and effector phases of the immune response, as well as in inflammatory reactions. T-cell activation requires interaction with antigen-presenting cells (APC), B-cell activation needs cognate interaction with T-cells, while cytotoxic T cells strongly bind target cells. Migration of leukocytes into inflammatory areas is mediated by a crucial step of leukocyte binding to endothelial cells followed by transendothelial migration. Adhesion molecules mediating these various cell to cell interactions belong to three families, i.e. the immunoglobulin superfamily, integrins and selectins.