Intravenous or Cold ex vivo Administration of Monoclonal Antibodies for Conditioning of Rat Small-Bowel Allografts

Abstract

The following study describes cold ex vivo or intravenous infusion of monoclonal antibodies (MCAB) for lymphocyte target cells of rat small-bowel grafts. The MCAB Ox8, directed against CD8+ T lymphocytes, is used here as a model antibody. We demonstrate that Ox8 antibodies administered during cold ex vivo perfusion are able to reach the target cells in the small-bowel mucosa and the mesenteric lymph nodes of rat small-bowel grafts. Thus, cold perfusion of the vascular system for 20–60 min resulted in good labelling of the CD8+ T cells as analysed on cryostat tissue sections using immunoperoxidase staining. Rats treated with Ox8 intravenously 60 min before taking of specimens showed similar labelling. Additional staining of the tissue sections with Ox8 antibody resulted in no further labelling, thus indicating that nearly all CD8+ T cells were labelled both after ex vivo perfusion and after intravenous treatment of the donor. It is concluded that MCAB can, as an alternative to the intravenous route, be administered ex vivo after organ harvesting.

Key Words:

• Graft-versus-host disease
• monoclonal antibodies
• rat
• T-cell antibodies
• transplantation