RESUMO
【Objective】 To understand the memory phenotype and function of SARS-CoV-2 reactive CD4+ T cells in healthy individuals. 【Methods】 In this study, SARS-CoV-2-derived peptides were used to stimulate PBMC from participants.SARS-CoV-2 reactive memory T cells were detected by intracellular staining and flow cytometry, and memory phenotype analysis was performed.CBA was used to detect cytokine secretion after SARS-CoV-2-derived peptides stimulation to evaluate the function of SARS-CoV-2 reactive memory T cells. 【Results】 We found that SARS-CoV-2 reactive CD4+ memory T cells could be detected in 40% (6/15) healthy donors.Phenotypic analysis of memory showed that these T cells were mainly composed of central memory T cells(82.2%), and other memory cells accounted for 17.8%.Compared with negative control, IL-10 was significantly decreased after stimulation of SARS-CoV-2-derived peptides (P<0.05), while the secretion of IFNγ, TNFα, IL-2 and IL-4 showed no significant difference. 【Conclusions】 SARS-CoV-2 reactive CD4+ memory T cells are present in healthy individuals from China.