Rheumatoid arthritis is an autoimmune disease that primarily affects joints and connective tissue in the heart and blood vessels in both men and women. It is especially prevalent in the United States, where more than 1.3 million people are affected. In previous research, it has been shown that one specific protein, labeled as Protein X, plays a critical role in the development of rheumatoid arthritis and of the inflammatory response behind it. It has been shown that levels of Protein X increased in synovial fluid and the serum of RA patients. However, its role is still quite unknown. To do this, we have made a collagen-induced arthritis mouse model to study the autoimmune effects of rheumatoid arthritis. A blocking antibody has been made that targets and blocks Protein X. We aim to find out whether or not a reduction in Protein X has any correlation with a reduction in clinical score in order to better understand the role of Protein X in RA. For this purpose, we have used several different methods consisting of bacterial transformation, intraperitoneal injections, and enzyme-linked immunosorbent assays (ELISAs) to perform this experiment.