Researchers from Harvard Medical School and Brigham and Women’s Hospital have developed a new method to detect a person’s viral history. VirScan tests for more than 1000 virus strains from a single drop of blood, and can identify past or present viral infections. The study, published in the journal Science, will have a positive effect in the clinic and immunology fields.
Viral infections can cause acute and chronic illness, but also can leave a long lasting effect in the host’s immune system. The interaction between the virome -the viruses that can affect humans- and the immune system can produce diseases like diabetes or asthma. However, their complex interplay has not been properly studied. Current methods to test the presence of a virus in an organism have a major limitation: they only test for one virus at a time, and tests are usually based on a physician’s hypothesis. A technique that detected multiple viruses at a time would eliminate speculation, errors and the need of multiple tests. Besides, correlational studies could be carried out to understand or discover virus-disease relationships, or their effect on certain population sectors.
A microarray that represents the whole human virome
Stephen Elledge and his team developed a new viral test that is as precise and cheap as the common ELISA test, but much more powerful. They created a microarray of epitopes -the peptides that viruses expose and that are recognized by the human immune system- representing more than 1000 viruses that affect humans. Due to the long life of immunological memory, antibodies generated by exposure to pathogens can still be detected many years after infection. VirScan’s epitope library will bind all antiviral antibodies found in human sera, and it just needs 1 uL of blood. The peptides recognized by antibodies are identified by immunoprecipitation and high-throughput DNA sequencing.
Elledge’s team tested the new system in 600 people from Africa, America and Asia, and found that viral exposure differs by age, HIV status and geography. They also discovered that a small number of epitopes where bound by most of the individuals, implying that the human immune system tends to recognize the same protein fragments in viruses.