(Singapore, July 17, 2020) A group of Singaporean scientists announced that they have uncovered the presence of a COVID-19-specific T cell immunity in healthy people, which could shed light on new treatment and vaccines of the deadly virus.
Their study, which was published in Nature, has uncovered the presence of virus-specific T cell immunity in people who recovered from COVID-19 and SARS, as well as some healthy study subjects who had never been infected by either virus.
“Our team also tested uninfected healthy individuals and found SARS-CoV-2-specific T cells in more than 50 percent of them,” said Professor Antonio Bertoletti, from Duke-NUS’ Emerging Infectious Diseases (EID) program, who is the corresponding author of this study.
“This could be due to cross-reactive immunity obtained from exposure to other coronaviruses, such as those causing the common cold, or presently unknown animal coronaviruses,” he said, noting that it is important to understand if this could explain why some individuals are able to better control the infection
The T cells, along with antibodies, are an integral part of the human immune response against viral infections due to their ability to directly target and kill infected cells.
The findings suggest infection and exposure to coronaviruses induces long-lasting memory T cells, which could help in the management of the current pandemic and in vaccine development against COVID-19.
The team, who comprise researchers from Duke-NUS Medical School and other institutes, tested subjects who recovered from COVID-19 and found the presence of SARS-CoV-2-specific T cells in all of them, which suggests that T cells play an important role in this infection.
Importantly, the team showed that patients who recovered from SARS 17 years ago after the 2003 outbreak, still possess virus-specific memory T cells and displayed cross-immunity to SARS-CoV-2.
Besides Duke-NUS Medical School, researchers from the National University of Singapore (NUS) Yong Loo Lin School of Medicine, Singapore General Hospital (SGH) and National Centre for Infectious Diseases (NCID) also contributed to the study.
Associate Professor Tan Yee Joo from the Department of Microbiology and Immunology at NUS Yong Loo Lin School of Medicine and Joint Senior Principal Investigator, Institute of Molecular and Cell Biology, A*STAR added, “We have also initiated follow-up studies on the COVID-19 recovered patients, to determine if their immunity as shown in their T cells persists over an extended period of time. This is very important for vaccine development and to answer the question about reinfection.”
“Their contributions, 17 years after they were originally infected, helped us understand mechanisms for lasting immunity to SARS-like viruses, and their implications for developing better vaccines against COVID-19 and related viruses,” said Dr Mark Chen I-Cheng, Head of the NCID Research Office.
Researchers say they will be conducting a larger study of exposed, uninfected subjects to examine whether T cells can protect against COVID-19 infection or alter the course of infection. They will also be exploring the potential therapeutic use of SARS-CoV-2-specific T cells.