To investigate the anti-inflammatory and immunomodulatory effects of the LACK156–173 epitope in arthritis, we synthesized rLACK (the synthetic polypeptide of the LACK156–173 epitope) and pLACK (the recombinant LACK156–173 epitope expression plasmid), and evaluated their effect on the development of CAIA, an animal model of RA. This evidence concerns the gene CAST and arthritic joint disease.