TLR4 and brucellosis: For instance, several factors of the innate immune system that in other bacterial infections play an essential role, seem to be of minor importance (e.g. iNOS, type-1 INFr, and gp91phox) or irrelevant (e.g. IL-1β, IL-18, TLR4, TLR5, TLR2, NOD1, NOD2, GM-CSF, IL/17r, Rip2, TRIF, NK or Nramp1s) in murine brucellosis.