Vasanthakumar G, Manjunath R, Mukherjee A B, Warabi H, Schiffmann E
Laboratory of Developmental Biology, National Institute of Dental Research, Bethesda, MD 20892.
Biochem Pharmacol. 1988 Feb 1;37(3):389-94. doi: 10.1016/0006-2952(88)90204-3.
Uteroglobin, a steroid-dependent secretory protein first discovered in the rabbit uterus during early pregnancy, is a potent phospholipase A2 inhibitor. We found that uteroglobin also inhibited human and rabbit phagocyte chemotaxis in response to formyl peptide attractants in a dose-dependent manner. Half-maximal inhibition was at 1.2 microM. Uteroglobin did not compete with a formyl peptide for its receptor but inhibited internalization of radiolabeled formyl peptide. Uteroglobin appears to inhibit chemotaxis by a mechanism different from that of dansylcadaverine, a well studied inhibitor of endocytosis. Unlike dansylcadaverine, uteroglobin did not have any effect upon the synthesis of phosphatidylcholine or phosphatidylinositol. It is suggested that uteroglobin may protect trophoblastic cells from the defense system of the host not only by binding to antigenic determinants of embryonic cells but also by impairing migration of phagocytes, one of the primary components of the immune defense system. These results may explain why embryonic cells do not elicit an inflammatory response in the uterine endometrium during pregnancy.
子宫珠蛋白是一种类固醇依赖性分泌蛋白，最早在妊娠早期的兔子宫中被发现，是一种有效的磷脂酶A2抑制剂。我们发现，子宫珠蛋白还能以剂量依赖的方式抑制人和兔吞噬细胞对甲酰肽趋化因子的趋化作用。半数最大抑制浓度为1.2微摩尔。子宫珠蛋白并不与甲酰肽竞争其受体，但能抑制放射性标记甲酰肽的内化。子宫珠蛋白似乎通过一种不同于丹磺酰尸胺（一种研究充分的内吞作用抑制剂）的机制来抑制趋化作用。与丹磺酰尸胺不同，子宫珠蛋白对磷脂酰胆碱或磷脂酰肌醇的合成没有任何影响。有人提出，子宫珠蛋白可能不仅通过与胚胎细胞的抗原决定簇结合，还通过损害吞噬细胞（免疫防御系统的主要组成部分之一）的迁移，来保护滋养层细胞免受宿主防御系统的攻击。这些结果或许可以解释为什么胚胎细胞在妊娠期间不会在子宫内膜引发炎症反应。
