Klima F, Tiemann U, Schadow D, Fasinski M, Savoly S B, Loose R, Pitra C
Vertebrate Research Centre, D-(0), Berlin, F.R.G.
J Reprod Immunol. 1992 Jan;21(1):57-70. doi: 10.1016/0165-0378(92)90040-b.
Maternal bovine EPF activity can be reduced to one single polypeptide enriched and identified from serum of cows in early pregnancy. The relative molecular weight of this active polypeptide was estimated at 67 kDa. This bovine EPF was labelled by 125I and peroxidase. In parallel investigations of non-pregnant animals a 67-kDa polypeptide was additionally identified in the last purification step, but without EPF activity in the rosette inhibition test. This indicated occurrence of an inactive pre-compound (or carrier protein) of the EPF in the non-pregnant state. On pre-incubation of lymphocytes with EPF analogues (inactive polypeptide from nonpregnancy serum) EPF retained its optimal activity, its lymphocyte receptors being unaffected. Monoclonal antibodies produced against HPLC-enriched EPF were reactive to the 67-kDa polypeptide in pregnancy material as well as in nonpregnancy material and were not able to differentiate between 'pregnant' and 'nonpregnant'. A mouse anti-EPF serum produced against highly purified EPF isolated from SDS PAGE showed reactivity only against the 67-kDa polypeptide of pregnancy serum but not against that of non-pregnancy serum. This is the first evidence for a difference in antigenic determinants of the two 67-kDa proteins found in pregnancy and non-pregnancy serum. Furthermore, a second higher molecular weight protein could be identified by this antiserum in pregnancy and non-pregnancy serum.
孕牛的早期妊娠因子（EPF）活性可降至单一多肽，该多肽从孕早期母牛血清中富集并鉴定得到。此活性多肽的相对分子质量估计为67 kDa。这种牛EPF用125I和过氧化物酶进行了标记。在对未孕动物的平行研究中，在最后纯化步骤中还鉴定出一种67 kDa的多肽，但在玫瑰花结抑制试验中无EPF活性。这表明在未孕状态下存在EPF的无活性前体化合物（或载体蛋白）。用EPF类似物（来自未孕血清的无活性多肽）对淋巴细胞进行预孵育时，EPF保持其最佳活性，其淋巴细胞受体未受影响。针对高效液相色谱法富集的EPF产生的单克隆抗体，对妊娠物质和未孕物质中的67 kDa多肽均有反应，且无法区分“妊娠”和“未孕”状态。用从十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS PAGE）分离得到的高度纯化的EPF制备的小鼠抗EPF血清，仅对妊娠血清中的67 kDa多肽有反应，而对未孕血清中的该多肽无反应。这是首次证明在妊娠和未孕血清中发现的两种67 kDa蛋白质的抗原决定簇存在差异。此外，用该抗血清可在妊娠和未孕血清中鉴定出另一种分子量更高的蛋白质。
