Jessen T E, Ødum L
Department of Clinical Biochemistry, Holbaek, Sygehus Vestsjaelland, DK-4300 Holbaek, Denmark.
Reproduction. 2003 Jan;125(1):27-31. doi: 10.1530/rep.0.1250027.
Binding of the plasma proteinase inhibitor inter-alpha-trypsin inhibitor (ITI) to hyaluronan is necessary for normal expansion of the cumulus-oocyte complex. Lack of ITI causes severe infertility. Binding of ITI to hyaluronan depends on calcium ions and coupling activity present in follicular fluid (Ødum et al., 2002). The complexes formed by this process contain ITI heavy chains bound to hyaluronan, and bikunin is detached from ITI during the coupling reaction. In the present study, an electrophoretic technique by which hyaluronan-bound ITI is immobilized was used to demonstrate that tumour necrosis factor stimulated gene 6 (TSG-6) is necessary for the coupling reaction. Thus, immunoprecipitation of TSG-6 in human follicular fluid eliminates the coupling reaction and re-addition restores the activity. However, it appears that components other than hyaluronan, ITI, calcium ions and TSG-6 are involved in the coupling reaction, as in vitro incubation of these components does not generate stable complexes between ITI heavy chains and hyaluronan unless some follicular fluid is added. In conclusion, TSG-6 is necessary for the coupling of ITI to hyaluronan, but at least one additional component in follicular fluid is essential.
血浆蛋白酶抑制剂α-胰蛋白酶抑制剂（ITI）与透明质酸的结合对于卵丘-卵母细胞复合体的正常扩张是必要的。缺乏ITI会导致严重的不孕症。ITI与透明质酸的结合取决于卵泡液中存在的钙离子和偶联活性（Ødum等人，2002年）。通过该过程形成的复合物包含与透明质酸结合的ITI重链，并且在偶联反应期间比基尼从ITI上脱离。在本研究中，使用一种将与透明质酸结合的ITI固定的电泳技术来证明肿瘤坏死因子刺激基因6（TSG-6）对于偶联反应是必要的。因此，人卵泡液中TSG-6的免疫沉淀消除了偶联反应，重新添加可恢复活性。然而，似乎除了透明质酸、ITI、钙离子和TSG-6之外的成分也参与了偶联反应，因为除非添加一些卵泡液，否则这些成分的体外孵育不会在ITI重链和透明质酸之间产生稳定的复合物。总之，TSG-6对于ITI与透明质酸的偶联是必要的，但卵泡液中至少还有一种其他成分是必不可少的。
