With the introduction of radio-immunoassays, published by Yalow and Berson in 1960, assays based on antibodies enable a specific measurement of analytes in complex biological samples. In 1977 Rosalyn Yalow was honored by the Nobel Prize in Physiology or Medicine “for the development of radioimmunoassays of peptide hormones”. With the rise of Western-blotting and enzyme-linked immunosorbent assays (ELISA) the underlying technologies rapidly entered life science and medical research. Continuous methodological improvements nowadays allow monitoring of nearly all kinds of known biological processes and a broad utilization in clinical diagnostics assigning immunoassay technology as an indispensable tool in current biomedical sciences.
One of the latest developments in this field is given by bead based multiplex immunoassays (xMAP® technology; Luminex), which enables the analysis of up to 500 different analytes “simultaneously” within only a few microlitres of sample amounts. Therefore these assays provide an appropriate and well established technology (several thousand peer reviewed publications) to overcome limitations given by traditional Western-blotting or ELISA. Next to reduced analysis costs and increased sensitivity, throughput capabilities and reproducibility, especially the minimal sample consumption, makes multiplex immunoassays applicable for investigations where sample amounts are extremely limited. Moreover, combining several analytes into assay panels offer the possibility to analyse complex protein signatures in one-shot. Due to the availability of a broad range of ready-made bead/antibody packages (e.g., Bio-Plex®-System; Bio-Rad: cytokines, growth factors and specialized disease state panels), dedicated calibration and validation tools together with special software for measurement and analysis this system helps to assure a high reproducibility and make this methodology particularly suitable for a standardized workflow. These features predestine multiplex immunoassays for its application within clinical biomarker research and validation.
In order to offer an opportunity to discuss this methodology in a scientific context we have picked out Bio-Plex® technology as the central theme for the International Protein Rainbow Workshop entitled BioPlex-Technology – Multiplicating ELISA, which was held at the Institute of Clinical Biochemistry and Pathobiochemistry at the German Diabetes Centre in Duesseldorf. This annual hands-on training course, comprising theoretical and practical aspects of the technology, was accompanied by a Bio-Plex User Meeting providing a dedicated platform to stimulate discussion and initiate co-operations between more than 40 scientists from various research areas.
As a summary this current issue “Multiplex immunoassays – An invaluable tool for biomarker discovery and validation” should help to give an overview of recent research related to multiplex immunoassays in biomedical research. Starting with a technical overview, introducing Bio-Plex® methodology, the collection of scientific reports covers a broad range of scientific applications in the clinical surrounding. As an example a study monitoring of complex immune response profiles during measles, mumps and rubella vaccination is presented. Another display the determination of macrophage migration inhibitory factor (MIF) in obese adolescents, whereby this study reveal increased MIF levels possibly representing a link between obesity and related co-morbidities. As an example for biomarker discovery, cytokine pattern were measured in peritoneal fluid from large group of endometriosis patients.