Flavonoid treatment of murine macrophages does not alter ingestion or intracellular survival of Listeria monocytogenes.

It was recently reported that the aryl hydrocarbon receptor (AhR) plays a role in innate immunity to Listeria monocytogenes infection in mice. In this study the authors analyzed whether incubation of murine macrophages with various flavonoids that have agonist or antagonist activity for the AhR (beta-naphthoflavone, alpha-naphthoflavone, quercetin, luteolin) affect the uptake and survival of L. monocytogenes. Using the RAW264.7 and J774 murine macrophage cell lines and bone marrow-derived macrophages, the authors found no significant difference between flavonoid-treated and control macrophages. They also found that macrophages incubated with flavonoids alone did not exhibit a significant increase in release of tumor necrosis factor (TNF)-alpha, a crucial cytokine in anti-Listeria resistance.