Here, we demonstrate in an Mx1-expressing mouse model of influenza A virus infection that a single intravenous injection of low-dose RIG-I ligand 5'-triphosphate RNA (3pRNA) completely protected mice from a lethal challenge with influenza A virus for at least 7 days.
RIG-I is an important RNA sensor to elicit the innate immune response in mammals and some bird species (such as duck) upon influenza A virus infection.
Known antiviral response pathways, including Toll-like receptor, RIG-I-like receptor, and direct interferon or cytokine stimulation did not alter the abundance of the tested miRNAs to the extent of influenza A virus infection, which initiates primary miRNA transcription via a secondary response pathway.
In this context, retinoic acid-inducible gene I (RIG-I) is the main cytosolic pattern recognition receptor known for detecting influenza A virus infection in mammalian cells.