TLR4 and infection: In this study, we observed lower levels of proinflammatory cytokines and chemokines in the BAL of TLR4-deficient mice in response to hMPV infection, which was paralleled by a reduction in inflammatory and immune cell recruitment, but did not seem to have a major impact on DC activation and their ability to support T cell proliferation and antibody production, suggesting that TLR4 sensing/transduction does not influence these immune functions in response to hMPV infection.