In the Journal of Immunological Methods, the researchers explain how they developed a test that may be able to identify diseases for which there are no known microbial causes.
Antigens are substances – such as bacteria, viruses, or chemicals – that induce an immune response in the body, causing the immune system to produce antibodies that target and destroy these foreign invaders.
However, there are a number of conditions for which there are no known antigens, including cancer, autoimmune diseases, and traumatic injuries, making them tricky to detect with current blood tests.
Senior study author Dr. Donald S. Burke, of the School of Public Health at the University of Pittsburgh, and colleagues explain that certain parts of these antibodies fit to the shape of molecules within the antigens in order to destroy them.
But Dr. Burke and colleagues believe this could change following the creation of their new blood test.
Peptoids and antibodies
For their study, the researchers used a technique pioneered by study co-author Thomas Kodadek, Ph.D., of the Scripps Research Institute in San Diego, CA, that can produce millions of molecular shapes called peptoids that are attached to microscopic plastic beads.
The team explains that if a peptoid matches a shape on an antibody, then that antibody will bind to it. The researchers can then remove the plastic beads and analyze both the peptoid and the attached antibody.
Even though the peptoids were created without the use of HIV proteins or structures, the team found the technique successfully located the molecular shapes in HIV antibodies that would be most likely to show up in HIV screening.
The researchers used the technique to produce a wide variety of peptoids and applied them to the blood of patients with and without HIV, with the aim of identifying peptoids that would only bind to HIV antibodies.
Technique accurately identified HIV-positive blood samples
Next, the researchers screened hundreds of HIV-positive or HIV-negative blood samples taken from the Multicenter AIDS Cohort Study – an ongoing study of HIV infection among homosexual and bisexual men.
The team found that the test was able to distinguish between HIV-positive and HIV-negative blood samples with a high level of accuracy.
The researchers resynthesized the peptoids that target HIV antibodies and applied them to the blood samples. The researchers who were testing the blood samples were unaware of which ones were positive or negative for HIV.
The authors say their findings bring us a step closer to being able to diagnose a myriad of diseases from just one drop of blood.
“This technology means that we may be able to take a single drop of blood from a patient and detect antibodies to all manner of infections, cancers or other conditions they may be carrying or been exposed to.
We hope that this is the first step toward development of an ‘Epi-chip’ that can be used to reconstruct a person’s entire exposure history.”
Dr. Donald S. Burke