In the context of experimental OM in the mouse, membrane-associated NTHi ligands, such as peptidoglycan and peptidoglycan-associated proteins (e.g. P6), are TLR2 ligands, and lipopolysaccharide activates TLR2 and TLR4 signalling (Leichtle et al., 2009). Here, TLR4 is linked to ocular melanoma.