Institute of Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.
PLoS One. 2012;7(4):e32716. doi: 10.1371/journal.pone.0032716. Epub 2012 Apr 4.
The generation of antibodies is impaired in newborns due to an immature immune system and reduced exposure to pathogens due to maternally derived antibodies and placental functions. During nursing, the immune system of newborns is challenged with multiple milk-derived proteins. Amongst them, caseins are the main constituent. In particular, human αS1-casein (CSN1S1) was recently shown to possess immunomodulatory properties. We were thus interested to determine if auto-antibodies to CSN1S1 are induced by breast-feeding and may be sustained into adulthood.
62 sera of healthy adult individuals who were (n = 37) or were not (n = 25) breast-fed against human CSN1S1 were investigated by a new SD (surface display)-ELISA. For cross-checking, these sera were tested for anti Epstein-Barr virus (EBV) antibodies by a commercial ELISA.
IgG-antibodies were predominantly detected in individuals who had been nursed. At a cut-off value of 0.4, the SD-ELISA identified individuals with a history of having been breast-fed with a sensitivity of 80% and a specificity of 92%. Under these conditions, 35 out of 37 sera from healthy donors, who where breast-fed, reacted positively but only 5 sera of the 25 donors who were not breast-fed. The duration of breast-feeding was of no consequence to the antibody reaction as some healthy donors were only short term breast-fed (5 days minimum until 6 weeks maximum), but exhibited significant serum reaction against human CSN1S1 nonetheless.
We postulate that human CSN1S1 is an autoantigen. The antigenicity is orally determined, caused by breast-feeding, and sustained into adulthood.
由于新生儿免疫系统不成熟，以及母体抗体和胎盘功能导致对病原体的接触减少，新生儿抗体的产生受到抑制。在哺乳期间，新生儿的免疫系统会受到多种乳源蛋白的挑战。其中，酪蛋白是主要成分。特别是人αS1-酪蛋白（CSN1S1）最近被证明具有免疫调节特性。因此，我们有兴趣确定是否通过母乳喂养诱导针对 CSN1S1 的自身抗体，并可能持续到成年。
使用新的 SD（表面展示）-ELISA 检测了 62 份来自健康成年个体的血清，这些个体（n=37）接受过母乳喂养，而（n=25）没有接受过母乳喂养，以针对人 CSN1S1 进行检测。为了交叉检查，这些血清通过商业 ELISA 检测抗 Epstein-Barr 病毒（EBV）抗体。
在接受过母乳喂养的个体中主要检测到 IgG 抗体。在 0.4 的截止值下，SD-ELISA 以 80%的敏感性和 92%的特异性识别有母乳喂养史的个体。在这些条件下，37 份来自母乳喂养的健康供体血清中有 35 份呈阳性反应，但在 25 份未接受母乳喂养的供体血清中仅有 5 份呈阳性反应。母乳喂养的持续时间对抗体反应没有影响，因为一些健康的供体只是短期母乳喂养（最短 5 天，最长 6 周），但仍然对人 CSN1S1 表现出明显的血清反应。
我们推测人 CSN1S1 是一种自身抗原。抗原性是通过口服决定的，由母乳喂养引起，并持续到成年。
