DIFFERENTIAL REACTIVITY OF ANTI-E-SELECTIN MONOCLONAL-ANTIBODIES IN HUMAN GINGIVAL TISSUE

E-selectin is a cytokine-inducible endothelial glycoprotein which part icipates in the binding of leukocytes to vascular endothelium. Variabl e levels of expression of E-selectin have been reported in gingivitis and periodontitis, and two differing concepts of its significance have emerged: either gingival blood vessels express E-selectin constitutiv ely, or are continuously activated by inflammatory mediators arising f rom the gingival environment. A range of monoclonal antibodies reactin g with different epitopes of E-selectin are available commercially The present study explored the possibility that the choice of antibody co uld affect estimation of the level of expression of E-selectin in vivo . Five monoclonal antibodies were used to investigate E-selectin expre ssion in serial cryosections of human gingival tissue. While E-selecti n-positive vascular endothelial cells were detected with all antibodie s, the number of positively staining endothelial cells varied, with BB A1 > H4/18 = H18/7 = 4D10 > 1.2B6. The frequency of strong staining in tissue specimens was BBA1 > 4D10 > H4/18 = H18/7 > 1.2B6, while the f requency of weak staining showed the reverse trend. Additionally, with antibodies H18/7 and 1.2B6, 17 and 36% of the specimens were E-select in negative. The occurrence of what appear to be false positives and f alse negatives confounds estimation of the level of E-selectin express ion. Based on these findings, patterns of endothelial E-selectin expre ssion in gingivitis and periodontitis should be re-evaluated.