Di Bartolo V, Balzan S, Pieraccini L, Ghione S, Pegoraro S, Biver P, Revoltella R, Montali U
CNR Institute of Mutagenesis and Differentiation, Pisa, Italy.
Life Sci. 1995;57(15):1417-25. doi: 10.1016/0024-3205(95)02104-q.
The identification in human plasma of ouabain as an endogenous digitalis-like factor (EDLF) claimed by Hamlyn et al. has recently been contradicted by two studies which failed to demonstrate endogenous ouabain-like immunoreactivity in HPLC fractions in which exogenous ouabain was eluted. In this paper we report the results obtained on the cross-reactivity with antiouabain antibodies of an EDLF purified by us from human newborn cord plasma. We found that this EDLF coeluted with ouabain on HPLC and cross-reacted both with rabbit anti-ouabain antiserum and with the purified antibodies, which excluded possible interferences due to antibodies directed against non-ouabain portions of the immunogen. Similar but not identical slopes of the ouabain and EDLF displacements curves were observed in all competition ELISA experiments. The inhibitory effect of EDLF on erythrocyte 86Rb uptake was reversed by antiouabain antiserum and antibodies. The concentration of EDLF in newborn plasma, in the four different purifications studied ranged from 30 to 380 pM ouabain equivalents (o.e.) by ELISA and from 100 to 300 pM o.e. by 86Rb uptake. Our data thus support the existence, in human newborn plasma, of a factor with both biological and immunological ouabain-like properties, although not necessarily identical to ouabain.
哈姆林等人宣称在人血浆中鉴定出哇巴因是一种内源性洋地黄样因子（EDLF），但最近两项研究对此提出了反驳，这两项研究未能在高效液相色谱（HPLC）中洗脱外源性哇巴因的组分中证明内源性哇巴因样免疫反应性。在本文中，我们报告了从人新生儿脐带血浆中纯化得到的一种EDLF与抗哇巴因抗体交叉反应的结果。我们发现这种EDLF在HPLC上与哇巴因共洗脱，并且与兔抗哇巴因抗血清和纯化抗体都发生交叉反应，这排除了由于针对免疫原非哇巴因部分的抗体可能产生的干扰。在所有竞争酶联免疫吸附测定（ELISA）实验中，观察到哇巴因和EDLF置换曲线的斜率相似但不完全相同。抗哇巴因抗血清和抗体可逆转EDLF对红细胞86Rb摄取的抑制作用。在所研究的四次不同纯化中，新生儿血浆中EDLF的浓度通过ELISA测定为30至380皮摩尔哇巴因当量（o.e.），通过86Rb摄取测定为100至300皮摩尔o.e.。因此，我们的数据支持在人新生儿血浆中存在一种具有生物学和免疫学上类似哇巴因特性的因子，尽管不一定与哇巴因相同。
