Hanson L A, Söderström T
Prog Clin Biol Res. 1981;61:147-59.
The neonate is deficient in the main antibody that protects mucosal membranes, the secretory IgA. While developing this immune system the breast-fed baby is provided with 0.25-0.5 grams per day of secretory IgA antibodies via the milk. These antibodies which function in concert with other defense factors in milk such as lactoferrin are directed against a number of micro-organisms that threaten the neonate. Recent studies suggest that it may be possible by vaccination of the mother to increase the immunity provided the breast-fed infant via the milk secretory IgA antibodies. Breast-feeding results in a lower frequency of infections in the infant, not only developing countries, but also in societies like Canada and USA. In developing countries the most dangerous period of a child's life begins with weaning when the protection of the breast milk vanishes and often heavily contaminated food is introduced. The large number of infections, especially diarrhea, that follow may be a major factor impairing growth and development with accompanying undernutrition. Utilization of available nutrients is much improved if these infections can be prevented.
新生儿缺乏保护黏膜的主要抗体——分泌型免疫球蛋白A。在发育免疫系统的过程中，母乳喂养的婴儿每天可通过母乳获得0.25至0.5克分泌型免疫球蛋白A抗体。这些抗体与母乳中的其他防御因子（如乳铁蛋白）协同作用，针对多种威胁新生儿的微生物。最近的研究表明，通过给母亲接种疫苗，有可能增加母乳分泌型免疫球蛋白A抗体为母乳喂养婴儿提供的免疫力。母乳喂养不仅在发展中国家，而且在加拿大和美国等社会，都能降低婴儿感染的频率。在发展中国家，儿童生命中最危险的时期始于断奶，此时母乳的保护作用消失，往往会引入污染严重的食物。随之而来的大量感染，尤其是腹泻，可能是阻碍生长发育并伴有营养不良的主要因素。如果能预防这些感染，可用营养素的利用率将大大提高。
