EXPRESSION OF 2 NOVEL RECOMBINANT PROTEINS FROM AORTIC ADVENTITIA (KAPPAFIBS) SHARING AMINO-ACID-SEQUENCES WITH CYTOMEGALOVIRUS

We have recently purified and partially sequenced a microfibrillar pro tein from human aortic adventitia (aneurysm-associated antigenic prote in, 40 kDa [AAAP-40]) that is immunoreactive with immunoglobulin (IgG) from the wall of abdominal aortic aneurysms (AAAs). It shares motifs with Ig kappa (which may act as a binding site for interaction with in tegrins), cytomegalovirus (which may be a molecular mimic in the patho genesis of AAA), and vitronectin and the fibrinogens. A cDNA library w as constructed from the aortic adventitia of a AAA. The library was sc reened with either rabbit anti-vitronectin antibody or rabbit anti-fib rinogen antibody. Positive plaques were purified and expressed in a st rain of Escherichia coli. The clone sequences were analyzed. The expre ssed proteins were separated by SDS/ PAGE and the immunoblots were pro bed with either AAA IgG or anti-human Ig kappa antibody. Experimental cell lines, transfected with the clones (clones 1 and 5), synthesized recombinant proteins (rAAAP-CL1 and rAAAP-CL5), detectable in Western immunoblots with AAA IgG. A prediction of the tertiary structure resem bles well-characterized cell adhesion molecules. These findings sugges t that there is a novel family of matrix proteins that may use immunog lobulin motifs as binding sites for cellular integrins and that there are matrix proteins in addition to AAAP-40 that may serve as autoantig ens in the pathogenesis of AAA disease. (C) 1997 Academic Press.