Antibodies are emblematic of the immune system, manufactured by the body in large quantities. Antibodies are tasked with recognizing and binding to antigens on invading pathogens to mark them for neutralization by other components of the immune system. Antibodies comprise three domains connected by thin, flexible linkages, enabling them to interact with multiple targets. The antigen-binding sites on the mouse antibody pictured are located at the tips of the arms projecting to upper right and to lower left. The image is a digital computer model based on real molecules. Magnification: 15 million times at 5"x7" printed size.