At sites of inflammation vascular endothelial  cells (EC) become activated by inflammatory cytokines and exhibit altered functions including increased adhesiveness for circulating leukocytes. In order to study EC activation further a monoclonal antibody 1.2 B6 was developed by immunizing mice with human umbilical vein EC activated for 6 hours with tumor necrosis factor a (TNE) 320 U/ ml. Antibody 1.2 B6 recognises the neutrophil adhesion related antigen ELAM-1 (Endothelial cell- leukocyte adhesion molecule-1). In culture ELAM-1 is not expressed no unassimilated EC but is rapidly induced on activation of EC with TNF,  interleukin-1 (IL1) or bacterial lip polysaccharide (LPS). Expression is maximal after 4 to re-stimulation with the same agent but can be reticulated with another. Since most studies of EC activation have been carried out using cultured large vein EC there exists a need to determine whether EC in tissues behave in a similar fashion. The aim of this study was therefore to investigate EC activation in skin organ cultures and acute and chronic inflammatory conditions of the oral mucosa mAb 1.2B6.

Results showed that ELAM-1 expression is modulated differently in the oral conditions examined and in vitro. In addition ELAM-1 expression may have to exceed a certain threshold before neutrophil adhesion and migration into the tissues can occur.