Molecular Cloning and Expression of 56-58 KD Antigen Associated with Transplant Coronary Artery Disease

Abstract

High circulating levels of anti-endothelial antibodies have been reported in patients with accelerated transplant coronary artery disease (TxCAD); however, the nature or characteristics of the antigen to which these antibodies bindin vivoremain unclear. To identify the antigen, a human endothelial cell cDNA expression library was constructed in λZAP and immuno-screened with serum containing a high titre of anti-endothelial antibodies. Nucleotide sequence of cloned cDNA inserts and GenBank database searches revealed a 94% identity in a 35 bp overlap to the human vimentin gene. The cloned antigen fusion protein co-migrated with human vimentin of molecular mass 56-58 KD in SDS-PAGE and exhibited immunoreactivity towards monoclonal and polyclonal anti-human vimentin antibodies. These results suggest that the 56-58 KD antigen associated with accelerated TxCAD is vimentin (or a vimentin-like protein), a cytoskeletal protein present in cells of the blood vessel walls.