Immunologic studies of bovine aortic and cartilage proteoglycans.

Rabbit antisera prepared against bovine cartilage and aortic proteoglycan monomer (PGM) were employed to identify and localize the distribution and cross-species reactivities of these PGMs. A specific reaction to both cartilage and aortic PGM was obtained as revealed by rocket immunoelectrophoresis of the immunogens against the respective antisera, with no reaction against bovine serum albumin or human fibronectin. These antisera appear to demonstrate tissue specificity. Indirect immunofluorescence studies with antiserum to aortic PGM on bovine aorta tissue revealed intense localization of fluorescence in the intima and superficial media with staining alone collagen fibers, around smooth muscle cells, and on the surface of elastin. When antiserum to cartilage PGM was applied to bovine aorta, staining was much weaker and localized more in the interfibrillar matrix. On the other hand, when antiserum to aortic PGM was used to stain bovine nasal septum cartilage, fluorescent staining was restricted to the pericellular matrix, in contrast to the diffuse, intense staining of both pericellular and extraterritorial staining by antiserum to cartilage PGM. Absorption with eigher bovine aorta or cartilage PGM abolished antibody activity against the absorbing molecules only. The immunologic distinction between the pericellular and extraterritorial cartilage matrix was demonstrated further when both antisera were studied with guanidine chloride (GuHCl)-extracted bovine nasal septum cartilage, when they both demonstrated the same pericellular matrix staining. Despite the tissue specificity, these antisera are not completely species specific, since staining in a similar pattern was observed in both human and rat tissues.