Researchers at the University of Texas Medical Branch (UTMB) have identified “two SARS-CoV-2 proteins that play a major role in helping the virus suppress the body’s early immune defenses.”

In a new study, scientists “examined how SARS-CoV-2 uses a collection of viral proteins to interfere with the innate immune response—the body’s first line of defense against infection.” The researchers specifically wanted to understand the relative importance of different proteins to dampening immune activity. They “engineered 12 recombinant versions of SARS-CoV-2, each carrying mutations in a different viral protein.”

Using those versions, the researchers “compared how the immune system responded to each modified virus. The study revealed that among 12 tested proteins, mutations in two—NSP1 and NSP15—triggered significantly stronger antiviral immune responses than the original virus, with nine of the 12 proteins showing some immune-suppressing activity.”

Using single-cell RNA sequencing, the researchers were also able to identify “broad changes in immune cell activation patterns in the lungs of infected mice, including effects on myeloid and lymphoid immune cell populations.” The findings demonstrate that ‘SARS-CoV-2 relies on multiple, overlapping mechanisms to suppress immune activity and avoid detection.”