Distribution of S-100 protein and glial fibrillary acidic protein in normal and gliotic human retina

Monoclonal antibodies and polyclonal antisera were used to examine the distribution of S-100 protein in human retinas both immunohistochemically and immunochemically and to compare it to that of glial fibrillary acidic protein (GFAP). S-100 was not found in normal retinas nor in retinas with areas of reactive gliosis. GFAP was found in perikarya and processes of cells the nuclei of which were in the nerve fiber layer of normal retina. In areas of reactive gliosis there was intense staining with antiserum against GFAP extending from the internal limiting membrane to the external limiting membrane. Some of the glial cells in human retina and fibrillary astrocytes in the brain are identical in their expression of GFAP. However, absence of S-100 from both quiescent and reactive retinoglia distinguishes them from astrocytes in brain and spinal cord.