Hall M O, Burgess B L, Abrams T A, Ershov A V, Gregory C Y
Jules Stein Eye Institute, UCLA School of Medicine 90095-7008, USA.
Exp Eye Res. 1996 Sep;63(3):255-64. doi: 10.1006/exer.1996.0114.
We have previously produced a polyclonal antiserum (R1S5) against a plasma membrane-enriched fraction of rat retinal pigment epithelial (RPE) cells which inhibits the phagocytosis of photoreceptor outer segments (OS) by these cells. This antiserum has now been used to purify a subset of RPE membrane glycoproteins. Using a combination of lectin affinity chromatography, and chromatography on an affinity column made with R1S5-IgG, we have enriched an RPE membrane extract about 100-fold. This enriched extract contains only 12 components, all of which are glycoproteins, and retains the ability to adsorb out the inhibitory activity of antiserum R1S5. This shows that one or more of these glycoproteins recognizes an inhibitory IgG in R1S5 and suggests that one or more of these glycoproteins may participate in the phagocytosis of OS by RPE cells, possibly as the phagocytosis receptor. We have performed N-terminal microsequencing of seven of these glycoproteins: four of the seven, with Mrs of 34, 36, 51 and 55 kDa, show no sequence homology to any known proteins.
我们之前制备了一种针对大鼠视网膜色素上皮（RPE）细胞富含质膜部分的多克隆抗血清（R1S5），该抗血清可抑制这些细胞对光感受器外段（OS）的吞噬作用。现在已使用这种抗血清来纯化RPE膜糖蛋白的一个亚组。通过结合凝集素亲和层析以及在由R1S5-IgG制成的亲和柱上进行层析，我们已将RPE膜提取物富集了约100倍。这种富集提取物仅包含12种成分，所有这些成分均为糖蛋白，并保留了消除抗血清R1S5抑制活性的能力。这表明这些糖蛋白中的一种或多种识别R1S5中的抑制性IgG，并表明这些糖蛋白中的一种或多种可能参与RPE细胞对OS的吞噬作用，可能作为吞噬受体。我们已对其中七种糖蛋白进行了N端微量测序：七种中的四种，分子量分别为34、36、51和55 kDa，与任何已知蛋白质均无序列同源性。
