Department of Nutrition, University of California, Davis, CA 95616, USA.
J Pediatr Gastroenterol Nutr. 2011 Dec;53(6):606-14. doi: 10.1097/MPG.0b013e318230a419.
Human lactoferrin (hLF), a major protein in human milk, has been shown to exert multiple biological activities. To achieve some of the benefits of breast-fed infants, we investigated the feasibility of adding commercially available bovine LF (CbLF) to infant formula.
An intestinal enterocyte model (Caco-2 cells) was used to compare the ability of bovine LF (bLF) purified by our laboratory and CbLF with hLF to resist digestion, bind to the receptor, and exert bioactivities, including cellular proliferation, differentiation, interleukin 18 secretion, and transforming growth factor-β1 expression.
bLf and CbLF, which are partially iron (Fe)-saturated, can bind additional Fe, partially resist digestion either dissolved in phosphate buffered saline or in the presence of infant formula at conditions similar to those of the infant gastrointestinal tract, and bind to Caco-2 cells in a manner similar to hLF. bLF and CbLF, as well as bound Fe, also are internalized by Caco-2 cells, as demonstrated by I and Fe labeling, albeit to somewhat less of an extent than hLF. CbLF promoted cell proliferation and differentiation to an extent similar to that of bLF and hLF, but these effects were not seen when the LF samples were saturated with Fe (holo-LF). Native forms of hLF and bLF significantly increased expression of transforming growth factor-β1, and holo-forms of LFs stimulated interleukin 18 secretion significantly, with the highest results for CbLF.
CbLF is biologically active and is likely to exert several of the bioactivities of hLF if added to infant formula.
人乳铁蛋白（hLF）是母乳中的主要蛋白质，具有多种生物学活性。为了实现母乳喂养婴儿的一些益处，我们研究了在婴儿配方奶粉中添加市售牛乳铁蛋白（CbLF）的可行性。
使用肠上皮细胞模型（Caco-2 细胞）比较了我们实验室纯化的牛乳铁蛋白（bLF）和 CbLF 与人乳铁蛋白抵抗消化、结合受体和发挥生物活性的能力，包括细胞增殖、分化、白细胞介素 18 分泌和转化生长因子-β1 表达。
部分铁（Fe）饱和的 bLF 和 CbLF 可以结合额外的 Fe，在类似于婴儿胃肠道条件的磷酸盐缓冲盐水或婴儿配方奶粉中溶解时，部分抵抗消化，并以类似于 hLF 的方式与 Caco-2 细胞结合。bLF 和 CbLF 以及结合的 Fe 也被 Caco-2 细胞内化，如 I 和 Fe 标记所示，尽管内化程度略低于 hLF。CbLF 促进细胞增殖和分化的程度与 bLF 和 hLF 相似，但当 LF 样品被 Fe 饱和（全铁-LF）时，没有观察到这些作用。天然形式的 hLF 和 bLF 显著增加转化生长因子-β1 的表达，全铁形式的 LFs 显著刺激白细胞介素 18 的分泌，其中 CbLF 的效果最高。
如果添加到婴儿配方奶粉中，CbLF 具有生物活性，并且可能发挥 hLF 的几种生物活性。
