[Lectin histochemical studies of retinal pigment epithelium following photocoagulation]

Lectins are histochemical probes for specific carbohydrate residues found in cell membranes and the cytoplasm. Lectin binding sites were determined in normal and morphologically altered retinal pigment epithelium (RPE) in photocoagulation scars using a modified PAP method. Tissue sections of human bulbi obtained during enucleation for various reasons were incubated with eight lectins of different sugar affinity: ConA, WGA, PNA, RCA I, SBA, UEA I, DBA, LPA. The comparative study of normal and reactive migrating and proliferating RPE revealed lectin binding sites for Con A, WGA, PNA and RCA I. Differences in the lectin binding pattern of various morphological cell types occurred within the intracellular topographical distribution and density of lectin binding sites. SBA, UEA I, DBA and LPA are not found to react with the RPE. These results indicate that lectin histochemistry allows cytochemical identification of normal and reactive RPE, which shows positive staining with Con A, WGA, PNA and RCA I not found in other cell types of retinal origin.