Providing cost-saving, rapid results, multi-analyte detection and analysis, and using only a tiny amount of sample, multiplexing is positioning itself as a premier technology in areas such as molecular diagnostics, patient treatment stratification, and as an essential research tool.
The young field is also tackling problems in reproducibility, efficiency, and data analysis. Whether it utilizes beads, chips, or qPCR technology, it’s providing increasing flexibility and muscle to the field. Examples include simplifying diagnostics for autoimmune disorders, automation for multiple research assays using magnetic beads, and adapting telecommunication technology to detect wavelength shifts resulting from biological interactions on a chip.
Dysregulation of the immune system can lead to self-attack by autoimmune antibodies. This often has devastating consequences leading to diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis, multiple sclerosis, etc.
“Most people do not know that up to 80% of our antibodies are directed against self antigens. Health problems arise when antibodies are not properly regulated,” says Peter Schulz-Knappe, M.D., CSO and executive vp diagnostics, Protagen.
Autoimmune disorders can be elusive to definitively identify. “Often, clinicians must order multiple types of tests to correctly diagnose such disorders. Laboratories may have 30–40 different tests that could be run, but this would require about 80 milliliters of blood from a patient.”
According to Dr. Schulz-Knappe, Protagen has been working to solve this problem. “Our company has miniaturized this analysis and now only one drop of blood is needed to run the equivalent of up to 500 microELISAs. We are utilizing the bead-based Luminex xMAP technology that can simultaneously analyze 500 analytes in a single sample.
“The polystyrene microspheres are color-coded with up to 500 unique colors. We take these and covalently attach each bead color with affinity-purified human proteins that are either well-known antigens or suspected to be novel targets of autoantibodies. We currently screen more than 6,000 human proteins that were expressed in an E. coli expression system and subsequently purified.”
Luminex’ xMAP technology analyzes the reactions using a dual laser light source that excites the internal dyes for bead recognition and simultaneous autoantibody quantification. If binding has occurred, the increase in fluorescence intensity is detected and analyzed by the software.
“We are currently using this technology to screen autoimmune clinical trial samples into responder or nonresponder categories. Although the majority of current efforts in personalized medicine have been applied to cancer treatment trials, we believe autoimmune analysis is also important.”
Dr. Schulz-Knappe says the company is utilizing a three-pronged approach. “First, we coat beads with known clinically relevant antigens. Second, we also are utilizing published but potential antigens that have not been clinically validated. Third, we are continuing to clone, express, and utilize more and more proteins from the human proteome.”
Thus far, Protagen has evaluated 7,000 patient samples for 15 different indications. “The challenges faced with the technology are membrane proteins such as receptors and ion channels. Those can be tricky proteins to produce. But, overall we expect to identify many more targets and are increasingly collaborating with partners. We see a great atmosphere and also envision many more patent applications.”