Various immune cells in the human body prevent diseases by maintaining a balanced immune system. Among them, T cells play the role of directly killing and eliminating virusinfected cells or cancer cells. Most patients infected with the novel coronavirus (SARSCoV- 2) experience mild symptoms and recover naturally, and T cell memory immune responses are known to form after recovery. SARS-CoV-2-specific T are expected to rapidly induce an immune response when encountering SARS-CoV-2 again, thereby allowing fast recovery from infection. However, due to the lack of detailed reports on the characteristics and functions of SARS-CoV-2-specific T cells in acute and convalescent COVID-19, the understanding of immune responses against SARS-CoV-2 has been limited. Against this backdrop, the research team led by Professor Eui-Cheol Shin became the world’s first to determine the characteristics and functions of SARS-CoV-2-specific T cells.

SARS-CoV-2-specific T cells activated in convalescent COVID-19

Instead of relying on conventional methods, the team led by Professor Eui-Cheol Shin employed the advanced research technique of MHC-I multimer staining to detect directly SARSCoV- 2-specific T cells. This approach made their study more challenging and difficult, but allowed higher sensitivity in T cell
detection, and a more detailed examination of their characteristics and functions. The team separated immune cells from the peripheral blood samples of acute and convalescent COVID-19 patients, directly detected SARS-CoV-2-specific T cells through MHC-1 multimer staining, and then performed cytokine secretion assays. The results showed that SARS-CoV-2-specific T cells were sufficiently produced and functional in the convalescent phase of COVID-19. In addition, normal memory T cell immune responses were triggered after recovery from COVID-19 infection, and the frequency of stem-like memory cells increased in the late convalescent phase, indicating that memory T cell immune responses can be maintained for a long time in convalescent individuals.


“Proud to correct misleading information in past research”

Professor Eui-Cheol Shin said, “Contrary to past research, we proved that SARS-CoV-2-specific T cells are not exhausted in COVID-19 convalescents. Our study has been evaluated as the most elaborate research on SARS-CoV-2-specific T cells.”

The study enables more sensitive and precise analysis of SARS-CoV-2-specific T cells, and will be a valuable reference for future research on COVID-19 vaccination. In particular, it is expected to contribute to the systematic analysis of how many SARS-CoV-2-specific T cells are produced and how long they
are maintained following the administration of newly developed COVID-19 vaccines. The results were published in the international journal Immunity on December 10, 2020.

Prof. Eui-Cheol Shin
2020 KI Annual Report