In Hybridoma technology, mAbs are produced by fusing antigen-activated B lymphocytes that have been immortalised with myeloma cells using polyethylene glycol. This technique was developed by Ceasar Milstein and George Kohler (Nobel Prize winners). The hybrid cells retain the ability of B cells to secrete antibody and the ability of myeloma cells to grow indefinitely. The hybrid clones when grown in culture produce epitope-specific mAb.

Antibodies bind to specific domains of antigens known as epitopes. The antibodies present in serum are a heterologous population released by different populations of B-Iymphocytes and therefore are known as polyclonal antibodies. The polyclonal antibodies can bind to related epitopes and are therefore do not give accurate results in diagnostics. Monoclonal antibodies (mAbs), on the other hand bind specifically to an epitope on an antigen and therefore are useful in detecting specific antigens (diagnostics) or blocking their binding by other molecules. Monoclonal antibodies provide accurate results and are therefore used in diagnostics.

Hybridoma technology has revolutionized the area of diagnostics and antibody-based therapies. The availability of monoclonal antibodies has helped in early detection of many infectious diseases like hepatitis and AIDS.