TF and infection: Although we cannot rule out the possibility that TF deficiency may have an effect on elaboration of proinflammatory cytokines at the very early stage of the M.tb infection, it is important to note here that expression of inflammatory cytokines in mice and guinea pig following M.tb infection was shown to occur around 2 to 3 weeks post infection, and the expression was persistent for 10 weeks or more [45], [46].