Clarke F M, Wilson S, McCarthy R, Perkins T, Orozco C
J Reprod Immunol. 1987 Feb;10(2):133-56. doi: 10.1016/0165-0378(87)90072-6.
Protocols are described for the isolation of substantial (mg) amounts of a rosette inhibition test (RIT)-active polypeptide fraction from ovine placental extracts. The main component of the preparation is a 12K polypeptide which contains a highly reactive thiol group. Oxidation may occur during isolation with the result that the final preparation is a mixture of the 12K polypeptide and a 25K disulphide linked dimer. The highly reactive thiol group was found to be directly involved in activity expression since gentle reduction followed by iodoacetylation resulted in a complete loss of activity. Antisera were prepared and the antibodies removed all the RIT activity from fresh ovine placental extracts, indicating that molecules related to those in the isolated preparation were responsible for all the activity in crude extracts. The antibodies also removed all the RIT activity from ovine and murine pregnancy sera, obtained both before and after implantation. Since EPF is defined as an RIT activity detected in pregnancy serum, these results establish that EPF activity is due to molecules similar to those isolated from the placental extracts. The availability of the preparative protocol and antibodies should hasten the biochemical definition of the EPF phenomenon.
本文描述了从绵羊胎盘提取物中分离出大量（毫克级）具有玫瑰花结抑制试验（RIT）活性的多肽组分的方法。该制剂的主要成分是一种含有高反应性巯基的12K多肽。在分离过程中可能会发生氧化，导致最终制剂是12K多肽和25K二硫键连接的二聚体的混合物。发现高反应性巯基直接参与活性表达，因为温和还原后进行碘乙酰化会导致活性完全丧失。制备了抗血清，这些抗体从新鲜的绵羊胎盘提取物中去除了所有的RIT活性，表明与分离制剂中的分子相关的分子是粗提取物中所有活性的原因。这些抗体还从植入前后获得的绵羊和小鼠妊娠血清中去除了所有的RIT活性。由于EPF被定义为在妊娠血清中检测到的RIT活性，这些结果表明EPF活性是由于与从胎盘提取物中分离出的分子相似的分子引起的。制备方法和抗体的可用性应会加速EPF现象的生化定义。
