Prolactin stimulates endocytosis of Staphylococcus aureus in bovine mammary ephithelial cells.

Bovine mastitis provokes inflammation of the mammary gland and is mainly caused by Staphylococcus aureus. Highest incidence occurs at drying off period and parturition, where prolactin (PRL) has a relevant function, although its role in the infection has not been studied. In this work, in vitro effect of the bovine PRL (1-50 ng/mL) on endocytosis and intracellular proliferation of S. aureus (ATCC 27543) in bovine mammary epithelial cells (BMEC) was evaluated. The BMEC treated during 24 h with 5 ng/mL of bPRL increases ~3 fold the endocytosis of S. aureus, besides inducing bacterial proliferation. This effect was specifically reverted by treating the BMEC with IgG anti-bPRL. S. aureus increased (~3 fold) its endocytosis in BMEC treated with bPRL (5 ng/mL), but the number of infected cells was not modified. In conclusion, the bPRL stimulates the endocytosis and the proliferation of S. aureus in BMEC. i [ABSTRACT FROM AUTHOR]