Characterization of E-selectin expression in vivo with use of a radiolabeled monoclonal antibody.

We have studied endothelial luminal surface expression of E-selectin in vivo in the pig. Intravenous interleukin-1 (IL-1, 5-micrograms/kg bolus +/- 50-ng.kg-1 x min-1 infusion for 2 h) induced E-selectin expression in many organs, as shown by immunostaining and selective clearance of intravenous 111In- or 99mTc-labeled anti-E-selectin monoclonal antibody (MAb 1.2B6) compared with radiolabeled immunoglobulin G1 control. Specific clearance of MAb 1.2B6 commenced 30-45 min after intravenous IL-1. Skin sites injected with IL-1, tumor necrosis factor, phytohemagglutinin, or phorbol myristate acetate at various times (45 min-24 h) before exsanguination showed specific accumulation of MAb 1.2B6 when 99mTc-MAb 1.2B6 and 111In-control immunoglobulin G1 were injected intravenously 10 min before exsanguination. This was maximal in 2-h IL-1 and tumor necrosis factor lesions and after 9 h in phytohemagglutinin and phorbol myristate acetate lesions. This novel approach has allowed us to quantify changes in vascular luminal expression of E-selectin in models of inflammation involving systemic and localized endothelial cell activation and has considerable potential for analyzing these changes in relation to leukocyte traffic and other manifestations of inflammatory responses in vivo.