A monoclonal antibody (mAb or moAb) is an antibody made by cloning a unique white blood cell. All subsequent antibodies derived this way trace back to a unique parent cell.

Monoclonal antibodies can have monovalent affinity, binding only to the same epitope (the part of an antigen that is recognized by the antibody). In contrast, polyclonal antibodies bind to multiple epitopes and are usually made by several different antibody secreting plasma cell lineages. Bispecific monoclonal antibodies can also be engineered, by increasing the therapeutic targets of one monoclonal antibody to two epitopes.

It is possible to produce monoclonal antibodies that specifically bind to virtually any suitable substance; they can then serve to detect or purify it. This capability has become an important tool in biochemistry, molecular biology, and medicine.

What are monoclonal antibodies?

Monoclonal antibodies (mAbs) are laboratory-created therapeutics precisely designed to target specific proteins in a variety of diseases, including asthma, cancer, autoimmune disorders such as rheumatoid arthritis, and, in a few cases, infectious processes. mAbs are one type of biologic product, as are vaccines, blood products, and others. Development of new mAbs has escalated rapidly over the past decade; as of 2019, the FDA had approved 79 different therapeutic mAbs, including 18 new antibodies in 2018 and 2019 alone. Human neutralizing antibodies play a key role in protective immunity for viral diseases, and are the focus of new mAbs under investigation to treat COVID-19.