Specific binding of radiolabeled anti–VCAM-1 mAb in rat skin and pleural membrane.

Panels A and B show the localization of radiolabeled anti–VCAM-1 mAb 5F10 in uninjected skin sites and skin sites injected with RPMI (100 μL) or IL-4 (5000 units/100 μL per site) and in pleural membranes after intrapleural administration of RPMI (100 μL) or IL-4 (5000 units/100 μL per cavity), respectively. In these experiments, localization of radiolabeled 5F10 was quantified in rats injected intravenously with the radiolabeled mAbs only (▪) and in rats injected with the radiolabeled mAbs and a 50-fold (1.25 mg of protein equivalent to 4.2 mg/kg) excess of unlabeled 5F10 (■). Expression of VCAM-1 in skin (A) and pleural membranes (B) is shown as the percentage of injected dose per gram of tissue (ID/g), corrected for the nonspecific uptake of the control mAb. Results are expressed as the mean ± SEM value for 6 to 8 animals (skin) or 3 to 7 animals (pleural membrane). Two asterisks indicate a significant difference (P < .001) from the uptake in uninjected skin sites or RPMI-treated pleural membranes.