Bauman W A, Yalow R S
Proc Natl Acad Sci U S A. 1981 Jul;78(7):4588-90. doi: 10.1073/pnas.78.7.4588.
The passage of plasma proteins across the placental barrier in humans is known to be highly selective. Thus, free maternal insulin has been reported not to cross the normal maternofetal barrier, although insulin-binding antibodies have been detected in newborn infants whose diabetic mothers received insulin therapy. In this report we demonstrate, with the use of a human antiserum that permits distinction between human and animal insulins, that insulin in the cord blood of each of two neonates of insulin-treated diabetic mothers was, in part, animal insulin. The higher the antibody titer of the mother the greater was the total insulin in the cord plasma and the greater was the fraction that was animal insulin. In case 1 cord plasma insulin was 0.7 unit/liter, of which 10% was animal insulin; in case 2 cord plasma insulin was 3.5 units/liter, of which 25% was animal insulin. The demonstration that antigen restricted from transplacental passage can be transferred while complexed to antibody raises the question whether such fetal exposure would induce partial or total immunologic unresponsiveness subsequently if the fetus were rechallenged with the same antigen.
已知人类血浆蛋白穿越胎盘屏障具有高度选择性。因此，有报道称游离的母体胰岛素不会穿过正常的母胎屏障，尽管在糖尿病母亲接受胰岛素治疗的新生儿中检测到了胰岛素结合抗体。在本报告中，我们使用一种能够区分人胰岛素和动物胰岛素的人抗血清证明，接受胰岛素治疗的糖尿病母亲所生的两名新生儿的脐血中的胰岛素部分为动物胰岛素。母亲的抗体滴度越高，脐血浆中的总胰岛素含量就越高，动物胰岛素所占比例也越大。在病例1中，脐血浆胰岛素为0.7单位/升，其中10%为动物胰岛素；在病例2中，脐血浆胰岛素为3.5单位/升，其中25%为动物胰岛素。抗原虽被限制通过胎盘，但与抗体结合时却能转移，这一发现引发了一个问题：如果胎儿随后再次接触相同抗原，这种胎儿暴露是否会导致部分或完全免疫无反应性。
