ABSTRACT
S-100 protein belongs to the family of ca-binding binding proteins such as calmodulin and troponin C- and had been considered to be specific for glial and Schwann cells. Recent immunohistochemical studies, however, have revealed the extensive localization of S-100 protein in a variety of cell types of neuroectodermal origin. In the present immunohistochemical study the localization of S-100 protein in the postnatal developing cornea of the rat was studied using a specific polycolonal antibody directed against S-100 protein in immunoperoxidase labelling experiments. S-100 protein was detected in the corneal epithelium, fibroblasts of substantia propria and the endothelium at the age of 10th postnatal day to the adult age. It did not give any activity before the age of 10 days. These results showed that S-100 protein was distributed in both ectodermal tissues [corneal epithelium] and mesodermal tissues [substantia propria and endothelium]. Also, this study suggests that S-100 protein could be expressed in the albino rat cornea just after its maturation and plays an important role in the corneal functions. Further investigations are, however, necessary to clarify the exact role played by S-100 protein in the cornea