Similarities of an autoantigen in aneurysmal disease of the human abdominal aorta to a 36-kDa microfibril-associated bovine aortic glycoprotein.

Immunoglobulin G (IgG) from human aneurysmal aorta was used to partially purify an aortic protein with an apparent MW approximately 80 kDa. Amino acid sequencing of a tryptic digest revealed two sequences with homology to mouse tenascin-X. The autoimmune IgG was then shown to react with purified human tenascin, and a rabbit polyclonal anti-human tenascin antibody was found to react with the purified autoantigen. These observations suggest that the autoantigen of abdominal aortic aneurysm disease may be homologous to a calcium-binding member of the tenascin superfamily that has been identified by others in pig and cow.