Infliximab is a chimeric monoclonal antibody used to treat various autoimmune diseases by binding to and inhibiting tumor necrosis factor-alpha (TNF-α), a key part of the autoimmune response. It was originally developed as a mouse antibody but was modified to contain mostly human antibody sequences. Infliximab is administered via intravenous infusion every 6-8 weeks and is approved by the FDA to treat Crohn's disease, ulcerative colitis, psoriasis, psoriatic arthritis, rheumatoid arthritis, and ankylosing spondylitis.