title: Role of bacterial components in macrophage activation by the LAC and MW2 strains of community-associated, methicillin-resistant Staphylococcus aureus.
abstract: We tested the contribution of four staphylococcal components - PSM-α, PSM-β, δ-toxin, and PVL - in triggering macrophage secretion of tumor necrosis factor (TNF) and interleukins 6 (IL-6) and 12 (IL-12) by two prominent, circulating strains of community-associated, methicillin-resistant Staphylococcus aureus (CA-MRSA): LAC, USA300; MW2, USA400. RAW 264.7 murine macrophages were stimulated with live, antibiotic-exposed bacteria, and cytokine secretion was quantitated in supernatants. Deletion of PSM-α expression in LAC led to >50% reduction in macrophage TNF and IL-6 secretion and a 20% reduction in IL-12 secretion, while PSM-α deletion in MW2 did not significantly reduce macrophage TNF secretion but resulted in a 15-20% reduction in IL-6 and IL-12 secretion. Deletion of δ-toxin in either strain led to more than 50% reduction in macrophage IL-6 secretion and smaller reductions in macrophage TNF and IL-12 secretion (8-25%). Our data implicate both PSM-α and δ-toxin in stimulating macrophage cytokine responses to CA-MRSA bacteria.
authors: Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, USA.
authors: Thomas
authors: T
authors: Spentzas
authors: Ravi
authors: R
authors: Kudumula
authors: Carlos
authors: C
authors: Acuna
authors: Ajay J
authors: AJ
authors: Talati
authors: Kimberly C
authors: KC
authors: Ingram
authors: Fabio
authors: F
authors: Savorgnan
authors: Elizabeth A
authors: EA
authors: Meals
authors: B Keith
authors: BK
authors: English
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000096:biosynthesis / Q000494:pharmacology*; D005098:Exotoxins / Q000096:biosynthesis / Q000494:pharmacology*; D008262:Macrophage Activation / Q000187:drug effects*; D055624:Methicillin-Resistant Staphylococcus aureus; D051379:Mice; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D001427:Bacterial Toxins; D005098:Exotoxins; D014409:Tumor Necrosis Factor-alpha