Daviet L, Morel-Kopp M C, Kaplan C, McGregor J L
INSERM Unit 331, Faculty of Medicine Alexis Carrel, Lyon, France.
Thromb Haemost. 1995 Mar;73(3):543-5.
The human CD36 antigen is an integral membrane glycoprotein expressed by platelets, monocytes, endothelial cells and various tumor cell lines. CD36 acts as a receptor for thrombospondin, collagen, Plasmodium falciparum-infected erythrocytes and oxidized low-density lipoprotein. Individuals possessing the Nak(a)-negative phenotype do not express CD36 and risk developing anti-CD36 isoantibodies upon blood transfusion or during pregnancy. In the present study, we have examined the interaction of an anti-Nak(a) serum with recombinantly expressed CD36. Results obtained show that five functional CD36 monoclonal antibodies (OKM5, FA6-152, L103, ESIV-C7 and 10/5) prevent the binding of the anti-Nak(a) serum whereas a single monoclonal antibody (13/10) has no effect. Consistent with this result, an epitope map of CD36 generated using cross-blocking experiments, indicates that the inhibitory monoclonal antibodies recognize closely-related epitopes whereas 13/10 reacts with a distinct CD36 determinant. Furthermore, we have demonstrated, in a recent study, that OKM5, FA6-152, L103 and 10/5 bind to the same CD36 domain defined by amino acids 155 to 183. Taken together, our results indicate that the 155-183 sequence is important for the binding of the anti-Nak(a) serum to CD36 and may represent a surface-exposed, immunogenic and presumably functional region on human CD36.
人类CD36抗原是一种整合膜糖蛋白，由血小板、单核细胞、内皮细胞及多种肿瘤细胞系表达。CD36作为血小板反应蛋白、胶原蛋白、恶性疟原虫感染的红细胞及氧化型低密度脂蛋白的受体。具有Nak(a)阴性表型的个体不表达CD36，在输血或妊娠期间有产生抗CD36同种抗体的风险。在本研究中，我们检测了抗Nak(a)血清与重组表达的CD36的相互作用。结果显示，五种功能性CD36单克隆抗体（OKM5、FA6-152、L103、ESIV-C7和10/5）可阻止抗Nak(a)血清的结合，而一种单克隆抗体（13/10）则无此作用。与此结果一致，利用交叉阻断实验生成的CD36表位图谱表明，抑制性单克隆抗体识别密切相关的表位，而13/10与一个不同的CD36决定簇反应。此外，我们在最近的一项研究中证明，OKM5、FA6-152、L103和10/5与由氨基酸155至183定义的同一CD36结构域结合。综上所述，我们的结果表明，155 - 183序列对于抗Nak(a)血清与CD36的结合很重要，可能代表人类CD36上一个表面暴露、具有免疫原性且可能具有功能的区域。
