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Member Research & Reports

Member Research & Reports

UNC Study Examines How Dangerous Respiratory Viruses Circumvent Body’s Defenses

Researchers at the University of North Carolina at Chapel Hill are studying how some of the most dangerous viruses on the planet tailor their defenses to get around the body’s immune system.The study, published in mBio, could contribute to a better understanding of how viruses such as H5N1 bird flu, the H1N1 flu, SAR,S and MERS viruses work to fool the body’s disease defenses. The study garnered immediate worldwide attention.

Dr. Ralph S. Baric, professor of epidemiology at the University of North Carolina Gillings School of Global Public Health and of m icrobiology and immunology in the School of Medicine, and his fellow researchers, several from UNC’s epidemiology department, compared host responses to such infections as severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV).

“Our data suggest an entirely new mechanism by which highly virulent respiratory viruses garner control of critical host defense programs to increase virus replication during infection” Dr. Baric said.

The data also spotlighted the ability of both SARS-CoV and MERS-CoV to inhibit recognition, delay interferon induction and sequester ISG production to try to neutralize the innate immune response.

Researchers used computers and empirical studies at UNC and the University of Wisconsin to gain insights into the viral mechanisms for manipulating and controlling ISG responses. For example, in cases where H1N1 virus provoked an immediate response by the body’s ISG, SARS was able to delay reaction by ISG and thereby establish itself more firmly in the host, making itself much more difficult to eradicate. Both MERS and H5N1 modify ISGs in a similar manner, illustrating similarities between these two highly lethal viruses, which cause mortality rates between 40 and 50 percent. MERS-CoV infections recently have increased dramatically in the Middle East, and three cases have appeared in the U.S.

The findings highlight strategies that highly pathogenic viruses use to control the host antiviral state. In each case, the strategy contributes to successful infection and may explain differences in virulence seen between viral families and strains.

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