Immunolocalisation of a 35K structural glycoprotein to elastin-associated microfibrils

Abstract

In this study, a rabbit antiserum directed against a 35K glycoprotein (35K-GP), extracted from connective tissue, was used to examine the localisation of this antigen within foetal bovine ligamentum nuchae at stages of development preceding (4th month) and coinciding with (7th month) active elastin biosynthesis. In these tissues the antibody, detected by a colloidal gold conjugate technique, localised specifically to 11-nm fibrils, identified as the microfibrillar component, present both in the form of independent bundles and in association with elastin in the developing elastic fibres. No other connective tissue component was recognised by the antibodies which had been purified by affinity chromatography. The ability of the antibodies to bind to the microfibrils appeared to be dependent on embedding in LR White resin, as colloidal gold binding was greatly reduced in tissue embedded in epoxy resin. These results are discussed with respect to the role that 35K-GP may play in the morphogenesis of the elastic fibre.