Lymphocyte adhesion to endothelium derived from human lymphoid tissue

The development of an efficient immune response depends on the capacity of antigen-specific lymphocytes to migrate into secondary lymphoid organs. The first step in the process of lymphocyte extravasation involves lymphocyte binding to the vascular endothelium. Although several adhesion receptors have been implicated in the migration of lymphocytes to inflamed tissue, their role in the extravasation of these cells to normal lymphoid organs is not yet clearly established. The involvement of adhesion molecules in lymphocyte entrance to secondary lymphoid organs can be better assessed in an in vitro system using endothelial cells in culture. Here we report on the isolation and culture of a homogeneous population of adherent cells of endothelial origin derived from human tonsils (TEC) and on adhesion studies performed with these cells. Beginning from primary cultures of human tonsils, we isolated a population of cells that we show by FACScan® analysis to present the intracellular endothel