Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), Institute of Pathology, University of Oslo, The National Hospital, Rikshospitalet, N-0027 Oslo, Norway.
Environ Toxicol Pharmacol. 1997 Nov;4(1-2):9-24. doi: 10.1016/s1382-6689(97)10036-9.
Much of the genetic information that modulates mucosal immune responses was encoded several million years ago and has subsequently been subjected to modifications selected by the impact of microorganisms and food antigens. Confronted with these challenges, the intestinal immune system has developed two arms: (1) immune exclusion performed mainly by secretory IgA antibodies to inhibit colonization of pathogenic microorganisms and penetration of harmful antigens; and (2) down-regulatory mechanisms to avoid local and peripheral overreaction (hypersensitivity) towards innocuous substances. The latter phenomenon is called oral tolerance and apparently explains why most individuals show no adverse immune reactions food. When the mucosal barrier function is insufficient, tolerance to dietary antigens is abrogated in genetically susceptible individuals. This is most likely to occur during the vulnerable period after birth before the immunoregulatory network has been established. Breast-feeding appears to be immunologically important during this period, not only to substitute for the infant's lacking secretory antibodies but also because of its immune-modulating effects.
在很大程度上，调节黏膜免疫反应的遗传信息是在数百万年前编码的，随后受到微生物和食物抗原影响选择的修饰。面对这些挑战，肠道免疫系统发展出了两条防线：（1）免疫排除，主要由分泌型 IgA 抗体来抑制致病性微生物的定植和有害抗原的穿透；（2）下调机制，以避免对无害物质的局部和外周过度反应（过敏）。后一种现象被称为口服耐受，它显然解释了为什么大多数人对食物没有不良反应。当黏膜屏障功能不足时，遗传易感个体对膳食抗原的耐受性会被破坏。这种情况最有可能发生在出生后的脆弱期，此时免疫调节网络尚未建立。母乳喂养在这段时间似乎具有重要的免疫作用，不仅可以替代婴儿缺乏的分泌型抗体，还因为它具有免疫调节作用。
