Antibodies in the blood. Animation of antibodies circulating in the bloodstream. Antibodies are proteins produced by the body as part of the immune response used to fight off infections. Typical antibodies include the y-shaped immunoglobulin. The 'limbs' of antibodies bind to foreign antigens such as the surface proteins of invading bacteria. Binding can neutralize toxins or invading organisms and prevent them from interfering with normal cell processes. Bound antibodies can also make it easier for white blood cells to digest antigens, as well as triggering the breakdown of foreign cells.