Toll Like Receptor 9 (TLR9)

Toll-like receptors (TLRs) recognize microbial products and initiate a complex immune response designed to eliminate invading pathogens.

TLR9 is specialized to recognize microbial nucleic acids, and 1 factor enabling TLR9 to discriminate between self and foreign DNA is the presence of unmethylated CpG dinucleotides in bacterial DNA (Hasan et al., 2007).other TLR proteins, TLR9 contains extracellular leucine-rich repeats (LRRs) and a cytoplasmic toll/interleukin-1R (TIR) domain. It also has a signal peptide (residues 1 to 25) and a transmembrane domain (residues 819 to 836). Northern blot analysis of mouse tissues revealed highest Tlr9 expression in spleen.