St Jacques S, Dadi H K, Letarte M
Division of Immunology and Cancer Research, Hospital For Sick Children, Toronto, Canada.
Placenta. 1993 Jan-Feb;14(1):25-39. doi: 10.1016/s0143-4004(05)80246-2.
CD44, a receptor for hyaluronic acid (HA), has been identified in the stroma of stem and terminal chorionic villi of human term placenta. The CD44 glycoprotein antigen, isolated from placenta by affinity to monoclonal antibody (mAb) 50B4, consisted mainly of species of M(r) 85,000 and 200,000. Radiolabelled CD44 bound specifically to HA attached to plastic, predominantly via the M(r) 85,000 species; this binding was inhibited by soluble HA and hyaluronidase. The binding of CD44 to HA was also inhibited by mAb 50B4 and IM7.8.1, which recognize epitopes of cluster I and II respectively, but was not blocked by a polyclonal antibody to peptide 18-30 of the B loop (residues 12-101). These results suggest that the portion of the B loop of CD44 implicated in the binding to HA is between amino acids 31-101 and that epitopes located outside the B loop, such as that recognized by mAb IM7.8.1 (between residues 132-215), contribute to this interaction. The presence of a functional CD44 molecule in the human term placenta suggest a role for this molecule in situ in the stabilization and orientation of HA network important in the maintenance of the structural integrity of the placenta.
CD44是一种透明质酸（HA）受体，已在人足月胎盘的干绒毛和终末绒毛基质中被鉴定出来。通过与单克隆抗体（mAb）50B4亲和从胎盘中分离出的CD44糖蛋白抗原，主要由分子量为85,000和200,000的分子组成。放射性标记的CD44特异性结合附着于塑料的HA，主要通过分子量为85,000的分子；这种结合被可溶性HA和透明质酸酶抑制。CD44与HA的结合也被分别识别簇I和簇II表位的mAb 50B4和IM7.8.1抑制，但不被针对B环（第12 - 101位氨基酸）18 - 30肽段的多克隆抗体阻断。这些结果表明，CD44的B环中与HA结合相关的部分在第31 - 101位氨基酸之间，并且位于B环之外的表位，如被mAb IM7.8.1识别的表位（第132 - 215位氨基酸之间），有助于这种相互作用。人足月胎盘中功能性CD44分子的存在表明该分子在维持胎盘结构完整性所必需的HA网络的稳定和定向中发挥原位作用。
