Influenza-induced immune suppression to methicillin-resistant Staphylococcus aureus is mediated by TLR9.

ABSTRACT: Bacterial lung infections, particularly with methicillin-resistant Staphylococcus aureus (MRSA), increase mortality following influenza infection, but the mechanisms remain unclear. Here we show that expression of TLR9, a microbial DNA sensor, is increased in murine lung macrophages, dendritic cells, CD8+ T cells and epithelial cells post-influenza infection. TLR9-/- mice did not show differences in handling influenza nor MRSA infection alone. However, TLR9-/- mice have improved survival and bacterial clearance in the lung post-influenza and MRSA dual infection, with no difference in viral load during dual infection. We demonstrate that TLR9 is upregulated on macrophages even when they are not themselves infected, suggesting that TLR9 upregulation is related to soluble mediators. We rule o

SUBMITTER: Martinez-Colon GJ 

PROVIDER: S-EPMC6364947 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature