ACTIVATION OF HIGH ENDOTHELIAL VENULES IN PERIPHERAL LYMPH-NODES - THE INVOLVEMENT OF INTERFERON-GAMMA

The introduction of Freund's complete adjuvant into footpads of mice l eads to functional changes of the high endothelial venules (HEV) in th e draining lymph nodes. Using an in vitro adhesion assay, increased bi nding of monocytes and dendritic cells could be seen. These effects ar e also seen after injection of high doses of IFN-gamma. No changes in the expression of vascular addressins, VCAM-1, E selectin or ICAM-1 co uld be observed but the binding of monocytes could be blocked with an antibody against Mac-1. Depletion studies have made it clear that macr ophages in the lymph node are not directly involved in the activation of the HEV. The induction of additional adhesion mechanisms on HEV cou ld be an efficient way to recruit inflammatory cells into the lymph no de, thereby regulating the local immune response.