A monoclonal antibody is a laboratory-made molecule designed to target specific proteins in the body. These antibodies are produced by identical immune cells cloned from a single parent cell, allowing them to bind to the same unique part of an antigen, such as a virus or cancer cell. This specificity makes them useful in both diagnostics and treatment. Monoclonal antibodies are used in various medical applications, including cancer therapy, where they can help the immune system recognize and destroy tumor cells. They are also employed in treating autoimmune diseases and in vaccines to enhance immune responses.