Isolation of Factors Causing Enhanced Lymphocyte Adherence to High Endothelial Venules in Vitro

Abstract

Circulating T and B lymphocytes bind to high endothelial cell venules (HEV) as the first step in their emigration from blood into lymph nodes (1–7). We have used an in vitro lymphocyte-HEV binding assay to probe the molecular mechanism of this process (8–12) and have isolated a glycoprotein factor from lymph which appears to be derived from shed lymphocyte surface molecules mediating the binding reaction (13, 14). The factor inhibits HEV binding in vitro, apparently by blocking sites to which lymphocytes normally attach. We now report the isolation from lymph and TDL supernatants of components designated adherence enhancing factors (AEF) which cause increased lymphocyte binding to HEV in vitro. These AEF have biological effects which suggest that they may play a physiological role in lymphocyte recirculation by promoting recognition between lymphocytes and high endothelium.