TLR3 is a member of the toll-like-receptor (TLR) family recognizing pathogen-associated molecular patterns.
TLR3 recognizes (virally derived) double- or single-stranded RNA leading to activation of immune cells. The natural ligands for TLR3 can be mimicked by synthetic RNAs (oligoribonucleotides; ORNs) like polyinosinic-polycytidylic acid (poly (I:C)), which hybridizes to form RNA double strands in aqueous solutions with ionic strength.