Antibodies are at the heart of all immunoassays. This chapter explains the basic biology and biochemistry of antibodies by way of introduction before an in-depth review of immunization and the various ways that antibodies are used as immunoassay reagents. The three main groups of antibody reagents are explained: polyclonal, monoclonal and recombinant, including preparation methods and their respective strengths and weaknesses. Bispecific, chimeric and humanized antibodies are described. The section on recombinant antibodies explains how to create a phage display antibody fragment library and how to select specific phage display antibodies, propagate them and improve the characteristics by modifying the amino acid sequence. Bispecific recombinant antibodies are reviewed, particularly diabodies and miniantibodies. Antibody fusion proteins are explained, consisting of the antibody and conjugated enzyme, avidin, biotin or other useful protein, in the same DNA sequence. Finally, there is a section advising on choosing between polyclonal, monoclonal and recombinant antibodies.

Eryl Liddell founded and led the Monoclonal Antibody Unit at the School of Biosciences at Cardiff University in the UK in 1983. This research and consultancy facility became involved in a broad range of projects based on antibody technology, with both national and international scope. It was one of the first centers to run a successful series of hands-on courses for scientists to learn hybridoma technology which resulted in the publication of a successful textbook on the subject.

Eryl has 33 years first hand experience in making and applying monoclonal antibodies in research and has taught countless students how to do so. She was a lead scientist in a group developing the first monoclonal antibodies to be applied in agricultural pest predation studies. More recently her focus has been in making unique antibodies for Alzheimer’s research.

Antibody, antigen, hapten, polyclonal antibody, monoclonal antibody, recombinant antibody, immunoglobulin, IgG, IgM, IgA, IgD, IgE, IgY, immunization, antibody response, constant region, variable region, epitopes, immunogenicity, glycoprotein, complementarity-determining region (CDR), Fab, F(abī)₂, bispecific antibody, immunoassay, B lymphocytes, class switching, affinity maturation, tolerization, VDJ gene, DNA immunization, immunoaffinity purification, immunoadsorption, myeloma, plasmacytoma, hypoxanthine guanine phosphoribosyl transferase, cell fusion, antibody screening, cloning, hollow fiber reactor, air-lift fermenter, ascites, hybridoma, humanization, purification, chimeric antibody, human anti-mouse antibody, CDR grafting, phage display, phage display library, panning, gene amplification, single-chain variable fragment (scFv), cloning, selectively infective phage, propagation, chain shuffling, mutagenesis, synthetic antibody, bivalent antibody, bispecific antibody, diabody, miniantibody, leucine zipper, antibody fusion proteins, combinatorial library, affinity, biopharmaceuticals, specificity.