TLR9 and infection: An in vitro infection of murine BMDMs isolated from TLR2-, TLR3- TLR4-, TLR7-, TLR9-, TLR2/TLR4-, and TLR2/TLR4/TLR9- deficient mice and cultured with Mtb showed that TLR9 was critical for protection against infection via FLT-3 ligand-generated DCs.