Brooker B E
Cell Tissue Res. 1983;229(3):639-50. doi: 10.1007/BF00207703.
The non-secretory epithelial cells which line the teat and lactiferous sinuses of the bovine mammary gland produce prominent pseudopodia which are able to ingest milk fat globules and casein micelles by phagocytosis. In the lactating gland, pseudopodia are uncommon and the phagocytosis of milk components less active than in the dry glands of cows which have not been milked for 2-3 weeks. Inside phagocytic vacuoles, casein micelles show morphological changes which suggest that digestion is taking place and the presence of acid phosphatase in vacuoles containing milk fat globules indicates that they too are degraded. The differences between lactating and dry glands in their phagocytic activity are reflected by corresponding differences in the number of epithelial cells containing acid phosphatase activity and in the intracellular distribution of the enzyme. It is suggested that the phagocytosis of milk components from the lumen of the dry gland assists in the resorption of milk and that the phagocytic potential of epithelial cells may, under some circumstances, play a role in the protection of the gland from invading bacteria.
排列在牛乳腺乳头和输乳窦的非分泌性上皮细胞会产生明显的伪足，这些伪足能够通过吞噬作用摄取乳脂肪球和酪蛋白胶粒。在泌乳期的乳腺中，伪足并不常见，并且与未挤奶2 - 3周的奶牛干奶期乳腺相比，对乳汁成分的吞噬作用不那么活跃。在吞噬泡内，酪蛋白胶粒呈现出形态变化，这表明消化正在发生，并且在含有乳脂肪球的泡内存在酸性磷酸酶表明它们也在被降解。泌乳期和干奶期乳腺在吞噬活性上的差异反映在含有酸性磷酸酶活性的上皮细胞数量以及该酶在细胞内分布的相应差异上。有人提出，从干奶期乳腺管腔中吞噬乳汁成分有助于乳汁的再吸收，并且上皮细胞的吞噬潜能在某些情况下可能在保护乳腺免受细菌入侵方面发挥作用。
