Illustration of antibodies (y-shaped) attacking a rhinovirus particle. The rhinovirus is the most common viral infectious agent in humans and is the predominant cause of the common cold. Antibody molecules have two arms that can bind to specific antigens, for instance viral proteins. In doing this they mark the antigen for destruction by phagocytes, white blood cells that ingest and destroy foreign bodies. Antibodies can also kill some pathogens directly and can neutralise toxins.