Polyinosinic-polycytidylic acid (usually abbreviated as poly(I:C) or poly(rI):poly(rC)) is a synthetic analog of double-stranded RNA (dsRNA), a molecular pattern associated with viral infection. Poly(I:C) activates the antiviral pattern recognition receptors TLR3, RIG-I/MDA5 and PKR, thereby inducing signaling via multiple inflammatory pathways, including NF-κB and IRF. Low Molecular Weight Poly(I:C) comprises short strands of inosine poly(I) homopolymer annealed to strands of cytidine poly(C) homopolymer. The average size of Poly(I:C) LMW is 0.2 kb to 1 kb.