A novel approach to discover new drugs against MS and other autoimmune diseases is disclosed. The p40 family of cytokines has four members which include interleukin-12 (IL-12), the p40 monomer (p40), the p40 homodimer (p402), and the IL-23. To facilitate the studies on p402 and p40, neutralizing monoclonal antibodies (mAb) against mouse p402 and p40 were generated for the first time. MS and other autoimmune disease drug therapies including recombinant p40 and/or monoclonal antibody against p402 (mAb-p402 a3-1d) are disclosed.
