| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 3416704 | Microbial Pathogenesis | 2011 | 6 Pages |
An early recruitment of neutrophils in mammary tissue and milk is considered an important component of the defense of the mammary gland against Staphylococcus aureus. We investigated whether the leukotoxin LukM/F′, which is produced by a proportion of mastitis-causing strains of S. aureus, would be able to trigger inflammation in the udder. Infusion of purified LukM/F′ toxin in lactating mammary glands did not cause neutrophil influx in milk, showing that the toxin was not able to cause mastitis on its own. Purified LukM/F′ did not kill or stimulate mammary epithelial cells in culture. As expected, LukM bound to mammary macrophages and the complete LukM/F′ toxin killed these cells, but subcytotoxic LukM/F′ concentrations did not induce secretion of IL-8, TNF-α, IL-1β or IL-6 by macrophages. On the contrary, the production of these pro-inflammatory mediators by adhesion-stimulated macrophages was reduced. Overall, these results indicate that purified leukotoxin LukM/F′ is not likely to contribute to the initiation of the inflammatory response and could even play an anti-inflammatory role in the mammary gland by inactivating macrophages.
► Purified Staphylococcus aureus leukotoxin LukM/F′ did not induce inflammation in the mammary gland. ► LukM/F′ toxin did not kill or stimulate mammary epithelial cells in culture. ► LukM/F′ killed mammary macrophages. ► Subcytotoxic concentrations of LukM/F′ reduced macrophage secretion of inflammatory cytokines. ► The LukM/F′ leukotoxin is not pro-inflammatory in the mammary gland.
