Interferon-gamma regulates an antigen specific for endothelial cells involved in lymphocyte traffic.

One of the most striking examples of localized vascular differentiation is exhibited by specialized lymphoid organ venules that mediate the extravasation of circulating lymphocytes from the blood. These vessels are characterized by cuboidal or "high" endothelial cell morphology and are unique in their functional capacity to interact with migrating lymphocytes, regulating both the rate and specificity of lymphocyte traffic through particular regions of the body. We describe here a monoclonal antibody, MECA-325, that defines an endothelial cell differentiation antigen selectively expressed on high endothelium in the mouse. Thus an antigen defining a specific functional subset of endothelial cells has been found. Furthermore, we demonstrate that the MECA-325 antigen can be induced in mouse lung or bone marrow-derived endothelial cell lines in vitro by interferon-gamma but not by interferon-beta, interleukin-1, or endothelial cell mitogens. The results define a unique marker associated with differentiated endothelial cells mediating lymphocyte traffic from the blood, and they provide evidence that the specialized phenotype of these high endothelial cells may be induced and controlled by local factors associated with immune activity.