Monoclonal antibodies are essential tools for many molecular immunology investigations. In particular, when used in combination with techniques such as epitope mapping and molecular modelling, monoclonal antibodies enable the antigenic profiling and visualisation of macromolecular surfaces. In addition, monoclonal antibodies have become key components in a vast array of clinical laboratory diagnostic tests. Their wide application in detecting and identifying serum analytes, cell markers, and pathogenic agents has largely arisen through the exquisite specificity of these unique reagents. Furthermore, the continuous culture of hybridoma cells that produce these antibodies oVers the potential of an unlimited supply of reagent. In essence, when compared with the rather limited supply of polyclonal antibody reagents, the feature of a continuous supply enables the standardisation of both the reagent and the assay technique. Clearly, polyclonal and monoclonal antibodies have their advantages and disadvantages in terms of generation, cost, and overall applications. Ultimately, monoclonal antibodies are only produced when necessary because their production is time consuming and frustrating, although greatly rewarding (at least most of the time!). This is especially apparent when a monoclonal antibody can be applied successfully in a routine pathology laboratory or can aid in the clinical diagnosis and treatment of patients. In this article, the generation and application of monoclonal antibodies are demystified to enable greater understanding and hopefully formulate novel ideas for clinicians and scientists alike.

The characterisation of monoclonal antibodies (MAbs) is essential for the development of assay systems particularly where antigens have been developed using synthetic peptides. Indeed some peptide-carrier conjugates fail to induce immune responses and may not generate antibodies that bind to native protein. As an alternative to peptide-carrier conjugates, multiple antigenic peptides (MAPs) have been used for immunization strategies, but with little regard to the characteristics of the MAbs produced. In this study, we used 3 MAPs of Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) to immunise BALB/c mice. Overall, the polyclonal antibody responses from tail bleeds showed that MAPs evoked B-cell responses. However, on screening 144 hybridomas, 24 MAb supernatants exhibited weak to moderate reactivity in enzyme-linked immunosorbant assay (ELISA) and against cell cytospin preparations (B95.8 and AG876 LCL), respectively. Isotype profiling of hybridoma supernatants also showed that 11 out of 24 were IgM. Further characterization of 6 MAbs in Western blotting showed reactivity to recombinant LMP1 and only one MAb (B28D) showed weak reactivity to the malignant cells (Hodgkin/Reed-Sternberg; HRS cells) of an EBV+ Hodgkin's lymphoma using paraffin-embedded tissue. It is probable that these MAPs failed to augment T-cell help and contributed to the production of low affinity (IgM) antibodies. These observations may be of importance to future immunization strategies, where MAPs are used in the production of monoclonal reagents.

The generation of monoclonal antibodies (MAbs) specific for quail neural crest may provide valuable tools for studying the differentiation of embryonic precursor cells. Unfortunately, relatively few antibodies are available because of the difficulty in obtaining sufficient cells for in vivo immunization strategies. We have overcome this problem by using intrasplenic immunization with formaldehyde-fixed cells harvested from neural crest cultures. In addition, booster injections of cultured whole-embryo cells were administered intraperitoneally. Following two fusions, a total of 18 hybridomas were generated with antibody reactivity to the cytoplasm of neural crest cells. Furthermore, 32 were reactive against both somite (a noncrest mesodermal control) and crest cultures, whilst 15 were not reactive. Out of those hybridomas reactive with neural crest, six designated 160D, 164D, OE, 12E, 120E and 124E were further characterized. Interestingly MAb supernatants OE, 12E, 120E, and 124E exhibited reactivity against some but not all neural crest cells suggesting that they might recognise subpopulations. Immunoglobulin isotyping of supernatants revealed that 4 (160D, 164D, OE, and 120E) were IgM and 2 (12E and 124E) were IgG(2b). On assessing their reactivity against human tissue sections, all six hybridoma supernatants cross-reacted with neuroendocrine cells within appendix, colon and rectum. These MAbs could provide novel reagents for the understanding of neural crest development.

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The characterization of monoclonal antibodies (MAbs) with regard to reactivity and specificity is important for the successful application as a molecular probe and/or diagnostic reagent. Furthermore, it is recognized that some monoclonal reagents perform well in some assay systems but not others. In this study, the reactivity profiles of two anti-myosin MAbs (H1 and DH2, raised against human cardiac myosin) were evaluated in enzyme-linked immunosorbent assay (ELISA), slot-blotting, and immunocytochemistry. Both antibodies performed well in slot-blotting against myosin heavy chain preparations from cardiac and skeletal muscle and from non-human sources. In general, MAb H1 demonstrated strong to moderate reactivity in all assay systems, whilst MAb DH2 faired poorly in ELISA. MAb H1 also showed reactivity to synthetic peptides of myosin, one of which possessed a motif (ERRDA, single amino acid code) that was found in other human and nonhuman myosin protein sequences that could explain its cross-reactive profile. Intriguingly, this motif was found on viral and other pathogenic agents associated with myocarditis. Hence, it is speculated that this region could give some credence to the mechanism of molecular mimicry associated with some cardiac diseases. Overall, MAb H1 may serve as a useful probe of myosin structure.