TNF and infection: Furthermore, YopM from different Yersinia strains reduced the production of proinflammatory cytokines (i.e. Interferon–γ (IFN-γ), Interleukin-1β (IL-1β), Tumor Necrosis Factor-α (TNF-α), Interleukin-15 (IL-15)) in mice at 1–4 days post infection [8, 25].