TNF and infection: While there is thus a correlation between increased mortality of MTb-infected NFATp-deficient mice and increased levels of NFATp-independent TNF in the early stages of infection, for both NFATp−/− and WT mice treatment with the TNF blocking agent Enbrel starting at 6 weeks post-infection significantly decreased survival, while injection at 12 weeks post-infection, when NFATp−/− and WT mice had comparable and relatively low serum levels of TNF, did not affect survival, indicating that the contribution of TNF against susceptibility to TB occurs in the early, acute phase of MTb infection.