The proinflammatory cytokine interleukin-17A (IL-17A) is produced primarily by the CD4+ T cell subset called Th17 cells, which is involved in host defense, inflammation, and autoimmune disorders. This study was undertaken to investigate the effect of a high-affinity RNA molecule, called an aptamer, against human IL-17A on IL-17A–induced signal transduction in vitro and its anti-autoimmune efficacy in vivo in 2 mouse models of inflammation.


By screening a large library of nuclease-resistant RNA oligonucleotides, we selected an RNA aptamer, Apt21-2, that binds human and mouse IL-17 and blocks the interaction between IL-17A and its receptor. The inhibition of IL-17A–mediated phosphorylation and marker protein production was analyzed in human and mouse cells. Mice with glucose-6-phosphate isomerase (GPI)–induced rheumatoid arthritis and myelin oligodendrocyte glycoprotein (MOG)–induced experimental autoimmune encephalomyelitis were used to assess efficacy.


Apt21-2 prevented efficient phosphorylation of the IL-17A signaling factors IκB and JNK and inhibited the production of IL-6 in human and mouse cells. A PEGylated form of Apt21-2 (PEG21-2idT) exhibited a 50% inhibition concentration (IC50) in the range of 1–2 nM and 70–80 nM in human and mouse cells, respectively. When administered immediately after immunization with GPI or MOG, PEG21-2idT inhibited in a dose-dependent manner the development of arthritic or neurologic symptoms. Significantly, PEG21-2idT slowed the progression of arthritis when administered after the onset of GPI-induced arthritis.


Our findings indicate that the chemically processed anti–IL-17A aptamer PEG21-2idT inhibits the actions of IL-17A as well as the development of autoimmunity in 2 mouse models of inflammation. These results offer for the first time an aptamer-based therapeutic approach to the treatment of Th17 cell–mediated autoimmune disorders.