In our in vitro infection model, we observed induction of a unique macrophage phenotype after S. aureus challenge, with several similarities with the M1 phenotype induced by LPS, such as production of the proinflammatory cytokines TNF-α, IL-12, and IL-6, known to stimulate epithelia, tissue, and other immune cells (32, 33). The gene discussed is TNF; the disease is infection.