Phagocytosis of Staphylococcus aureus by somatic cells in dry cow secretion of mammary gland.

Independently of the stage of the dry period, phagocytosis and killing of Staphylococcus aureus by somatic cells isolated from dry cow secretion were significantly higher in a medium of diluted secretion than in 1% serum and in PBS. Intramammary introduction of vaccine from killed Staphylococcus aureus cells caused, in the steady state dry period, the significant increase of phagocytic and bactericidal activity of somatic cells, examined in the medium of diluted secretion of the mammary gland. The isolated secretion deriving both from vaccinated and non-vaccinated cows causes--in the steady state dry period--the disappearance of the significance of differences between the somatic cells coming from various cows. Phagocytosis is highly significantly correlated with the total and intracellular survival of bacteria; similarly, highly significant correlation exists between the total and intracellular survival of S. aureus.