Washington (ISJ) ? Medical scientists at Harvard Medical School and Brigham and Women?s Hospital developed a technology to test more than 1,000 different strains of viruses from a single drop of blood. The new methods known as VirScan could simultaneously detect viruses that may have infected a person ?currently or previously?.
It sheds light on the interplay between a person?s immunity and the human virome ? a vast array of viruses that can infect humans ? with implications both for the clinic and for the field of immunology. The findings were reported in Science on June 05.
?What makes this so unique is the scale: right now, a physician needs to guess what virus might be at play and individually test for it. With VirScan, we can look for virtually all viruses, even rare ones, with a single test,? said Stephen Elledge, Gregor Mendel Professor of Genetics and Medicine at Harvard Medical School, the author of the study.
Classic blood tests, known as ELISA assays, can only detect one pathogen at a time. Additionally, ELISA assays have not been developed against all viruses. The team found the sensitivity and specificity of VirScan to be very similar to that of ELISA assays. The test cost is also comparable.
Elledge and his colleagues tested blood samples from almost 600 people from Peru, the United States, South Africa and Thailand. They developed and used a library of peptides ? short protein fragments derived from viruses-representing more than 1,000 viral strains to find evidence of previous viral exposure.
Rate of viral exposure varied by age, geographic location and HIV status, but the team found that a small number of peptides were recognized by the vast majority of people?s immune systems. This pattern, suggesting that the immune systems of many individuals are hitting upon the same protein portion in a virus, could have important implications for understanding immunity.
VirScan may also help researchers find correlations between previous exposure to a particular virus and the development of a disease later in life. A connection between Epstein-Barr virus ? one of the most common viruses seen in this study-and the risk of certain kinds of cancer is already known. The new method may help reveal other as-yet-unknown connections.
?A viral infection can leave behind an indelible footprint on the immune system,? said Elledge. ?Having a simple, reproducible method like VirScan may help us generate new hypotheses and understand the interplay between the virome and the host?s immune system, with implications for a variety of diseases.
