SELECTIVE INDUCTION OF PERIPHERAL AND MUCOSAL ENDOTHELIAL-CELL ADDRESSINS WITH PERIPHERAL LYMPH-NODES AND PEYERS PATCH CELL-CONDITIONED MEDIA

Vascular endothelial cell addressins play an important role in lymphoc yte homing in secondary lymphoid organs and in chronic inflammatory ar eas, A SV40 large T antigen-immortalized cell line from peripheral lym ph nodes, HECa10 [Bizouarne et al., 1993a], was used to characterize t he location of addressins with regard to environmental factors and cyt okines, For this purpose, two monoclonal antibodies, MECA 79 and MECA 367, specific for peripheral lymph node vascular addressin and for muc osal addressin (Peyer's patches), respectively, were bound to unstimul ated HECa10 cells, Both mucosal and peripheral addressins were detecte d inside the cells and in cellular extracts of the resting cells, On t he cell surface, both addressins could be evidenced on the same cells at a moderate level of expression, They partly mediate the EL4/EL4IL2 lymphoma cells' adhesion to HECa10 cells, Supernatants of cultured per ipheral lymph node or Peyers' patch cells induced expression of MECA 7 9 or MECA 367 antigens, respectively, on the surface of HECa10 cells, Interleukins, IL,?, IL-3, and IL-8, induced the cell-surface appearanc e of MECA 79 but not of MECA 367 antigen, Therefore, the same cell typ e synthesizes both antigens, but the expression of these antigens on t he cell surface is independently regulated, thus uncovering a characte ristic tissue type-specific as well as environment-sensitive propertie s of microvascular endothelial cells.