Staphylococcus aureus inhibits nuclear factor kappa B activation mediated by prolactin in bovine mammary epithelial cells

► Staphylococcus aureus and prolactin as NF-κB regulators in mammary epithelial cells. ► Prolactin induces NF-κB activation and Staphylococcus aureus internalization. ► Staphylococcus aureus inhibits NF-κB activation in the presence of prolactin. ► NF-κB inhibition down-regulates gene expression of innate immune response.