AUTHOR=Zhang Yunwen , Yang Zhengrong , Tang Mingyuan , Li Hao , Tang Tian , Li Guilian , Zhong Yifan , Zhang Xiaomin , Wang Xiaohui , Wang Chuan 

TITLE=Three Specific Potential Epitopes That Could Be Recognized by T Cells of Convalescent COVID-19 Patients Were Identified From Spike Protein

JOURNAL=Frontiers in Immunology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.752622

DOI=10.3389/fimmu.2022.752622

ISSN=1664-3224

ABSTRACT=The current COVID-19 vaccines are used to prevent viral infection by inducing neutralizing antibody in the body, but according to the existed experience of SARS infection, T cell immunity could provide longer durable protection period than antibody. The research on SARS-CoV-2 specific T cell epitope can provide target antigen for the development and evaluation of COVID-19 vaccines, which is conducive to obtain COVID-19 vaccine that can provide long-term protection. For screening specific T cell epitopes, a SARS-CoV-2 S protein peptide library with a peptide length of 15 amino acids was synthesized. Through flow cytometry to detect percentage of IFN-γ+ T cells after mixed COVID-19 convalescent patients’ peripheral blood mononuclear cell with peptide library, seven peptides (P77, P14, P24, P38, P48, P74 & P84) that can be recognized by the T cells of COVID-19 convalescent patients were found. After excluding the non-specific cross-reactions with unexposed population, three SARS-CoV-2 specific T cell potential epitopes (P38, P48 & P84) were finally screened with the positive reaction rates between 15.4% and 48.0% in COVID-19 convalescent patients. This study also provided the HLA allele information of peptide-positive-response COVID-19 convalescent patients, thus predicting the population coverage of these three potential epitopes. Some HLA alleles showed higher frequency of occurrence in COVID-19 patients than in total Chinese population, but no HLA alleles related to the T cell peptide response and the severity of COVID-19. This research provides three potential T cell epitopes that are helpful for the design and efficacy evaluation of COVID-19 vaccines. The HLA information provided by this research supplies reference significance for subsequent research, such as that to find the relation of HLA genotype with disease susceptibility.