Bopp S, el-Hifnawi E, Laqua H
Fortschr Ophthalmol. 1989;86(5):515-8.
Lectins are sugar-binding proteins or glycoproteins which bind to specifically complementary sugar residues found in cell membranes and the cytoplasm. Lectin-binding sites are determined by histochemical methods. Cellular lectin-binding sites change with morphological and functional alterations of the cell, and the determination of lectin receptors can be used to identify specific cell types in histological sections. Lectin-binding sites of the human retinal pigment epithelium (RPE) and photoreceptor cells under normal and pathological conditions have not been examined. Lectin-binding sites of normal retinal pigment epithelium and photo-receptor cells obtained from enucleated human bulbi were identified by a modified PAP method. Eight lectins differing in their sugar affinity (Con A, WGA, PNA, RCA I, SBA, UEA, DBA, LPA) were used to investigate a wide range of glycoconjugate specificity. Normal RPE have receptors for the lectins Con A, WGA, PNA and RCA I, mostly localized in the apical portions of the cells. Binding sites for these lectins are also found on photoreceptor cells, but with different binding characteristics. Photoreceptor cells bind additional lectins (UEA, SBA, DBA), which are not found on the RPE.
凝集素是一类能与细胞膜及细胞质中特定互补糖残基结合的糖结合蛋白或糖蛋白。凝集素结合位点通过组织化学方法确定。细胞凝集素结合位点会随着细胞形态和功能的改变而变化，凝集素受体的测定可用于在组织切片中识别特定细胞类型。目前尚未研究过正常和病理条件下人视网膜色素上皮（RPE）和光感受器细胞的凝集素结合位点。采用改良的过氧化物酶抗过氧化物酶（PAP）法鉴定了从摘除的人眼球中获取的正常视网膜色素上皮和光感受器细胞的凝集素结合位点。使用了8种糖亲和力不同的凝集素（刀豆球蛋白A、小麦胚凝集素、花生凝集素、蓖麻凝集素I、大豆凝集素、荆豆凝集素、双花扁豆凝集素、扁豆凝集素）来研究广泛的糖缀合物特异性。正常RPE具有刀豆球蛋白A、小麦胚凝集素、花生凝集素和蓖麻凝集素I的受体，主要定位于细胞顶端部分。在光感受器细胞上也发现了这些凝集素的结合位点，但结合特征不同。光感受器细胞还结合其他凝集素（荆豆凝集素、大豆凝集素、双花扁豆凝集素），而这些凝集素在RPE上未发现。
