RLR-receptors : important elements of innate immunity

The paper presents the RLRs (RIG-I-like receptors) that are members of PRRs (pathogen recognition receptors) and are found on immunity system cells, binding to structures originating from germs, called as PAMP (pathogen-associated molecular patterns). PRRs are divided on secreted receptors, surface receptors engaged in phagocytosis and cell activating receptors or receptors expressed on immunity and other cells surface. RLRs belong to the third group of PRRs. Among RLRs there are RIG-I receptor (cytosolic double-stranded RNA helicases retinoic-acid-inducible gene I) i MDA5 receptor (melanoma differentiation-associated gene 5). Both RIG-I and MDA5 play a major role in recognition of RNA viruses in DCs, macrophages and fibroblasts. There has been shown that RIG-I binds 5’-triphosphorylated ssRNA and short dsRNA viruses whereas MDA5 preferentially recognizes longer-dsRNA. RLRs are receptors of innate immunity, that are very important in antiviral response. It seems that those receptors determine significant defense line in viral infection and restrict replication and invasion of pathogens.