TLR4 and infection: Our data suggest a possible dual role for TLR4 during infection with certain strains of Mtb, since its activation not only induced type I IFN, that may result in increased susceptibility [15], [52], [54], [56], but simultaneously induced the expression of protective cytokines (e.g. TNF) and of iNOS, a molecule known to be important for the control infection [57].