However, although mRNA level of TNF-α was remarkably upregulated, the production of TNF-α was only detectable at 24 h post-infection (hpi) at low level (20 pg/mL, data not shown), which may be due to the TNF-α production mainly from activated immune cell types, such as macrophages (Locksley et al., 2001; Stow et al., 2009). The gene discussed is TNF; the disease is infection.