Monoclonal antibodies:

Specific antibodies derived from a single (mono) clone of plasma cells. It may be produced in large quantities, usually for use against a specific antigen, for diagnostic and possibly therapeutic use. 

Antibodies specific for a single antigen. They can be produced in large quantities in the laboratory. Monoclonal antibodies are being studied in clinical trials to determine their effectiveness in cancer detection, diagnosis, and treatment. 

Immunoglobulin molecules of single- epitope specificity that are secreted by a clone of B cells. 

("MAb") are antibodies secreted by a hybridoma clone, each such clone being derived from a single B cell (lymphocyte) that produces a specific antibody. 

Antibodies are proteins that help white blood cells fight off viruses and bacteria, by binding to foreign invaders and signaling the immune cells to attack. Monoclonal antibodies are antibodies that are made in the laboratory to bind to only one single type of molecule. They are currently being used to bind to tumor cells, either to signal to immune cells to attack, or to carry toxic agents directly to the tumor.