Identification of HLA-A2 restricted CD8⁺ T cell epitopes in SARS-CoV-2 structural proteins

Area of Science:

• * Immunology and Virology
• * Infectious Disease Research

Background:

• * The COVID-19 pandemic, caused by SARS-CoV-2, highlights the need to understand T cell-mediated immunity for viral control.
• * Limited knowledge exists regarding the immunogenicity of SARS-CoV-2 proteins and induced immune response mechanisms.
• * Identifying specific T cell epitopes is vital for advancing vaccine development and therapeutic strategies.

Purpose of the Study:

• * To predict and identify immunogenic HLA-A2 restricted CD8+ T cell epitopes within SARS-CoV-2 structural proteins.
• * To evaluate the immunogenicity and functional capacity of predicted epitopes in activating CD8+ T cells.
• * To contribute to a deeper understanding of SARS-CoV-2 specific immune responses.

Main Methods:

• * Utilized the Immune Epitope Database and NetMHCpan for in silico prediction of HLA-A2 restricted CD8+ T cell epitopes.
• * Employed a T2A2 cell binding model to assess peptide binding affinity to HLA-A2.
• * Conducted in vitro assays to measure CD8+ T cell activation (CD69 expression, IFN-γ, granzyme B production) and cytotoxic activity.

Main Results:

• * Predicted 23 potential HLA-A2 restricted CD8+ T cell epitopes; 18 demonstrated strong or moderate binding.
• * Administered mixed peptides induced significant CD8+ T cell activation, evidenced by increased CD69, IFN-γ, and granzyme B levels.
• * Activated CD8+ T cells exhibited enhanced killing of target cells, with tetramer staining identifying seven key recognized epitopes.

Conclusions:

• * Successfully identified specific CD8+ T cell epitopes in SARS-CoV-2 structural proteins capable of inducing immune responses.
• * Demonstrated that these identified epitopes can activate CD8+ T cells, leading to enhanced viral control mechanisms.
• * The findings provide valuable insights for SARS-CoV-2 vaccine design and the development of targeted immunotherapies.