TNF and viral infectious disease: M1, which is activated by interferon-γ (IFN-γ) or lipopolysaccharides (LPS), produces pro-inflammatory cytokines such as interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-α), nitric oxide (NO), and reactive oxygen intermediates and promotes a polarized type I immune response to mediate host defense against bacterial, protozoa, and viral infection, as well as tumor cells 4-6.