HUMAN SCLERAL ELASTIC SYSTEM - AN IMMUNOELECTRON MICROSCOPIC STUDY

An immunocytochemical study was conducted on elastic components in the sclera of seven aged human eyes. By conventional electron microscopy, elastic tissue consists of three distinct fibre types - elastic fibre s, elaunin fibres, and oxytalan fibres. The distribution of six compon ents associated with the elastic system (elastin, amyloid P component, laminin, fibronectin, gp 115, and vitronectin) were studied by immuno gold transmission electron microscopy. The codistribution of amyloid P component and laminin was further studied by double immunolabelling. Both elastic and elaunin fibres contained elastin. The microfibrillar sheaths of elastic fibres labelled for amyloid P component, those of e launin fibres for amyloid P and laminin, and those of oxytalan fibres for laminin only. No labelling was observed for fibronectin, gp 115, a nd vitronectin. In terms of the proteins investigated, the biochemical profile of the three fibre types was not completely identical and was manifest as different affinities in the binding of serum amyloid P co mponent and an association with laminin.