Collagens and non collagenous proteins in the human eye. I. Corneal stroma in vivo and keratocyte production in vitro.

Human corneal stroma in situ and keratocyte activity in vitro were studied by the indirect immunofluorescent technique using highly purified antibodies to the various types of collagens, fibronectin and laminin. Studying the localization of the various collagens in situ, it was observed that only type I collagen is present in the human corneal stroma. No positive immunofluorescence is obtained for type II or type III collagen. With type IV collagen, a bright immunofluorescence is observed at the level of Bowman's and Descemet's membranes. However, in vitro, the keratocyte cultures demonstrated the production of both type I and III collagens. No evidence for the production of type II or IV collagens was observed. Along with the collagens, human keratocytes in vitro also produced fibronectin. As for the non collagenous components of basement membrane (laminin), although a positive immunofluorescence was obtained the involvement of other cell-membrane glycoproteins in this reaction is not excluded. The possibility that a deregulation of type III collagen synthesis in vivo might be occurring also during certain pathologies and in corneal wound healing is postulated.