Patel V P, Ciechanover A, Platt O, Lodish H F
Proc Natl Acad Sci U S A. 1985 Jan;82(2):440-4. doi: 10.1073/pnas.82.2.440.
We describe three situations in which a large fraction of circulating red blood cells attach tightly and specifically to fibronectin: (i) rabbits made anemic by repeated bleeding, (ii) patients with hemolytic anemia and functional asplenia and splenectomized normal humans, and (iii) splenectomized mice. Upon induction of anemia in rabbits, the proportion of circulating red blood cells capable of specifically attaching to fibronectin-coated plastic increased in parallel with the number of reticulocytes. Fibronectin-adherent red cells were barely detectable when the rabbit had recovered from the anemia. Attachment of reticulocytes to fibronectin was specific; cells did not attach to dishes coated with albumin, laminin, or collagen. None of these proteins promoted the attachment of normal erythrocytes. About 75% of the erythrocytes from splenectomized mice (but not control mice) also attached specifically to fibronectin 40 days after surgery. The effect of splenectomy was incomplete and transient; adherent cells were not detectable 8 weeks after splenectomy. As judged by labeling studies with [35S]methionine, newly emergent reticulocytes preferentially attached to fibronectin. We suggest that about half of the reticulocytes in erythropoietically unstressed mice lose their ability to attach to fibronectin, possibly due to loss of fibronectin-adhesive components, during passage through the spleen. The others lose their ability to interact with fibronectin before release, in the bone marrow, or in some extrasplenic site.
（i）因反复出血而贫血的兔子，（ii）患有溶血性贫血和功能性无脾症的患者以及脾切除的正常人，（iii）脾切除的小鼠。在兔子发生贫血时，能够特异性附着于纤连蛋白包被塑料的循环红细胞比例与网织红细胞数量平行增加。当兔子从贫血中恢复后，几乎检测不到纤连蛋白黏附的红细胞。网织红细胞与纤连蛋白的附着是特异性的；细胞不附着于涂有白蛋白、层粘连蛋白或胶原蛋白的培养皿。这些蛋白质均未促进正常红细胞的附着。脾切除术后40天，约75%的脾切除小鼠（而非对照小鼠）的红细胞也特异性地附着于纤连蛋白。脾切除的效果不完全且短暂；脾切除术后8周无法检测到黏附细胞。通过用[35S]甲硫氨酸进行标记研究判断，新出现的网织红细胞优先附着于纤连蛋白。我们认为，在造血未受刺激的小鼠中，约一半的网织红细胞在通过脾脏的过程中，可能由于纤连蛋白黏附成分的丧失，失去了附着于纤连蛋白的能力。其他网织红细胞在释放前、在骨髓中或在某些脾外部位失去了与纤连蛋白相互作用的能力。
