Establishment and Characterization of a Lactating Caprine Mammary Gland Luminal Epithelial Cell Line

Mammary gland is a defining characteristic of mammalian species which produces nutritious milk and plays a major role in the development of newborns. The gland contains a series of ducts and crevices leading back to alveoli, which contain milk producing cells called luminal epithelial cells. These cells, if cultured in-vitro, can be utilized to explore the metabolic processes occurring during milk production. The knowledge thus gained can be used to manipulate the system to enhance milk production and/or modify its composition. The main objective of this study was to establish a luminal epithelial cell-line from a lactating goat. Explant culture technique was used to produce primary cells from the mammary tissue of a 4-year-old lactating Saanen goat. The outgrowing cells were purified by selective trypsinization to remove fibroblast cells in 3-4 serial passages. The purified cell cultures exhibited cobblestone morphology, typical of the mammary epithelial cells, formed clear islands when plated in low density, and exhibited dome-shaped structures, if cultured for extended time. The cells stained positive with anti-human cytokeratin 18 antibodies, confirming their epithelial nature. Cell cultures also stained positive with rabbit anti-bovine β-lactoglobulin antibodies, indicating milk production in these cells. The cell-line has potential as an in-vitro cell model to understand signaling during milk synthesis, mammary gland development, and testing DNA constructs for therapeutic protein secretion in milk, prior to production of transgenic goats.