TRIL or TLR4 interactor with leucine rich repeats, is a protein encoded by the human KIAA0644 gene. TRIL protein sequence is highly conserved across species. It is expressed in a number of tissues with highest expression in brain, ovary, small intestine and spleen. TRIL is an accessory molecule that interacts with TLR3 and endosomal TLR4, enhancing their interaction with their ligands, poly(I:C) and LPS, and increasing the production of type I interferons in the innate immune response.