TLR2 and rheumatoid arthritis: The blockade of TLR2 by OPN301 (an IgG1 monoclonal anti-TLR2 antibody) in cells of patients with rheumatoid arthritis was found to decrease the production of TNF, IL-1β and IFN-y after stimulation with Pam3Cysk4 (a TLR2 agonist) (23).