Antibodies that are produced by a plasma cell derived from a single B cell, and which therefore bind to exactly the same antigen, are called antibodies.

Antibodies that are produced by a plasma cell derived from a single B cell and which bind to exactly the same antigen are called monoclonal antibodies.

Explanation

Monoclonal antibodies are engineered to target a specific antigen, which makes them highly valuable in various applications, including diagnostic tests, therapeutics, and research. They are produced through a process that involves the fusion of a specific type of immune cell, called a B cell, with a myeloma (cancer) cell. This fusion results in a hybrid cell known as a hybridoma, which can replicate indefinitely while producing a specific antibody.

The term "monoclonal" refers to the fact that all the antibodies produced by these cells are identical and derived from a single clone of B cells, allowing for a consistent and reproducible response to a particular target. This is in contrast to polyclonal antibodies, which are produced by multiple B cell lineages and can recognize different epitopes on the same antigen. Monoclonal antibodies have revolutionized medicine, especially in treatments for diseases like cancer and autoimmune disorders.