Golimumab is a monoclonal antibody used in the treatment of autoimmune diseases, particularly rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and ulcerative colitis. Golimumab targets and inhibits tumor necrosis factor alpha (TNF-_), a cytokine involved in the inflammatory pathway that contributes to autoimmune diseases. By blocking TNF-_, golimumab helps to reduce inflammation and alleviate symptoms associated with these conditions.