Practical applications of some antibodies labelling the human retina

Eight enucleated eyes were promptly fixed in 10% formalin and processed for light microscopy. Employing the ABC technique, we used antibodies against neuron-specific enolase (NSE), synaptophysin (SY), neurofilament (NF), glial fibrillary acidic protein (GFAP), keratins, LEU-7 and S-100 protein. Using NSE we found immunoreactivity in all sensory layers except the outer segments of photoreceptors which were nonreactive. SY showed a striking immunoreactivity of the synaptic regions (outer plexiform and inner plexiform layers). NF labelled the axons of the ganglion cells. GFAP stained perivascular glial cells and Müller cells only in areas of peripheral microcystoid degeneration. Keratin was non-reactive in all layers. LEU-7 showed that all layers were moderately reactive while the Müller cell processes and the outer limiting membrane were strongly immunoreactive. S-100 protein stained the perivascular glial cells in the nerve fiber layer. We conclude that NSE and LEU-7 are helpful markers for most layers of the sensory retina; GFAP and LEU-7 clearly outline Müller cells and GFAP immunoreacts with astrocytes; NF is specific for axons and SY labels vividly the synaptic regions.