Vaccine Targets for Coronavirus Identified

A team of scientists at the Hong Kong University of Science and Technology (HKUST) has recently made an important discovery in identifying a set of potential vaccine targets for the SARS-CoV-2 coronavirus, providing crucial leads for guiding experimental efforts towards the vaccine development against the novel pneumonia (COVID-19) caused by the virus. Their findings were published yesterday in the journal Viruses.

Like SARS-CoV, which caused the SARS (Severe Acute Respiratory Syndrome) outbreak in 2003, SARS-CoV-2 belongs to the same Betacoronavirus genus. By considering the genetic similarity between SARS-CoV-2 and SARS-CoV, the team leveraged experimentally determined immunological data to identify a set of SARS-CoV-derived B cell and T cell epitopes that exactly match to SARS-CoV-2. As no mutation has been observed in the identified epitopes among the available SARS-CoV-2 genetic sequences, immune targeting of these epitopes may potentially offer protection against the novel pneumonia COVID-19.

“Despite similarities between SARS-CoV and SARS-CoV-2, there is genetic variation between the two, and it is not obvious if epitopes that elicit an immune response against SARS-CoV will likely be effective against SARS-CoV-2,” says senior author Matthew McKay. “We found that only roughly 20% of the SARS-CoV epitopes map identically to SARS-CoV-2 and believe these are promising candidates.”

According to coauthor Ahmed Quadeer, the researchers also performed a population coverage analysis on identified T cell epitopes in order to determine a set of epitopes that “is estimated to provide broad coverage globally as well as in China.” The estimated population coverage represents the percentage of individuals within the selected population that are likely to elicit an immune response to at least one epitope from the identified set.

“Our objective was to try to assist with the initial phase of vaccine development by providing recommendations of specific epitopes that may potentially be considered for incorporation in vaccine designs,” McKay says. “More generally, our work is part of a global effort seeking to capitalize on data for COVID-19, made available and rapidly shared by the scientific community, to understand this new virus and come up with effective interventions.”

The beginning of 2020 has seen the emergence of SARS-CoV-2 outbreak in mainland China, which has quickly spread to over 30 countries around the world, infecting over 80,000 people and causing over 2,600 deaths as of late February 2020.

Image: B cell epitopes that map identically to SARS-CoV-2. Image courtesy of HKUST.