Lectin binding to the human retina

Formalin-fixed, paraffin-embedded tissue sections of the human retina were stained with different fluorescein isothiocyanate-conjugated lectins. The lectins used were concanavalin A (Con A), Triticum vulgaris (WGA), glycine maximum (SBA), Dolichos biflorus (DBA), Ulex europaeus (UEA I), Arachis hypogaea (PNA), and Ricinus communis (RCA I). Con A stained both the inner and outer segments of the rods and cones, whereas WGA stained the inner and outer segments of the rods and the outer segments of the cones. PNA selectively stained only the inner segments of the cones. In addition, Con A and WGA stained neuron cytoplasm and nerve fibers in different layers of the retina. The results obtained differ in some important aspects from those previously obtained in the frog and monkey retina; this finding may be due to species differences. The results of lectin staining in the normal human retina may form the basis for future studies of retinal diseases.