Inflammatory arthritis: imaging of endothelial cell activation with an indium-111-labeled F(ab')2 fragment of anti-E-selectin monoclonal antibody

Abstract

Purpose: To use imaging performed with an indium-111-labeled F(ab')2 fragment of monoclonal antibody that recognizes E-selectin (1.2B6) to evaluate inflammation.

Materials and methods: After the in vivo immunoreactivity of In-111-F(ab')2 was verified, imaging experiments were conducted on pigs with induced arthritis of the right knee. In-111-labeled 1.2B6-F(ab')2, technetium-99m-hexamethylpropyleneamine oxime-labeled polymorphonuclear leukocytes (PMNs), and iodine-125-MOPC 21-labeled F(ab')2 (the control) were administered by means of intravenous injection. Scintigrams were obtained until 20 hours after injection, and tissue sampling was performed.

Results: Scintigrams showed uptake of 1.2B6 in the right knee but only faint filling of the joint space with PMNs. The right knee-to-left knee ratios on images obtained 20 hours after injection of the tracers were 10.8 +/- 3.6 for 1.2B6 and 1.1 +/- 0.4 for PMNs (P < .05).

Conclusion: Endothelial cell immunotargeting with a radiolabeled anti-E-selectin F(ab')2 monoclonal antibody is feasible for use in imaging of inflammation.