In a major development, a study conducted by Scientists in Singapore from Duke-NUS Medical School, in close collaboration with the National University of Singapore (NUS) Yong Loo Lin School of Medicine, Singapore General Hospital (SGH) and National Centre for Infectious Diseases (NCID) has revealed that infection and exposure to coronaviruses induce long-lasting memory T cells, which could help in the management of the current pandemic and in vaccine development against COVID-19. The newly found study is published in journal Nature.

Scientists in Singapore University uncovered T cell immunity specific to SARS-CoV-2 in recovered COVID-19 & SARS patients, and also in uninfected individuals.

What are T cells?

T cell, a type of leukocyte (white blood cell) is an essential part of the immune system at the core of adaptive immunity. Along with antibodies, T cells are part of the human immune response against viral infections. The T cells directly target and kill infected cells. The T cells are like soldiers who search out and destroy the targeted invaders.

The role of T cells also includes directly killing infected host cells, activating other immune cells, producing cytokines and regulating the immune response.

What has the study found?

In the study by the Duke–NUS Medical School, specific T cells were found in all subjects who recovered from SARS 17 years ago after the 2003 outbreak and in over 50% of both SARS-CoV-1 and SARS-CoV-2 uninfected individuals tested. The researchers said that according to this result, a level of pre-existing SARS-CoV-2 immunity is present in the general population.


"Our team also tested uninfected healthy individuals and found SARS-CoV-2-specific T cells in more than 50 per cent of them. 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. It is important to understand if this could explain why some individuals are able to better control the infection," Professor Antonio Bertoletti, the corresponding author of this study at the Duke-NUS' Emerging Infectious Diseases (EID) programme was quoted as saying to ScienceDaily.

Researchers of this study revealed that it could be possible due to cross-reactive immunity obtained from exposure to other coronaviruses, such as those causing the common cold. 

Associate Professor Jenny Low, Department of Infectious Diseases, SGH, and Duke-NUS' EID programme on the importance of this study said, “While there have been many studies about SARS-CoV-2, there is still a lot we don't understand about the virus yet. What we do know is that T cells play an important role in the immune response against viral infections and should be assessed for their role in combating SARS-CoV-2, which has affected many people worldwide. Hopefully, our discovery will bring us a step closer to creating an effective vaccine.”

According to Science Daily, a team of scientists will be now focussing to conduct 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.

Posted By: Simran Babbar