Abstract
As the establishment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cell memory in children remains largely unexplored, we recruited convalescent COVID-19 children and adults to define their circulating memory SARS-CoV-2-specific CD4 + and CD8 + T cells prior to vaccination. We analyzed epitope-specific T cells directly ex vivo using seven HLA class I and class II tetramers presenting SARS-CoV-2 epitopes, together with Spike-specific B cells. Unvaccinated children who seroconverted had comparable Spike-specific but lower ORF1a- and N-specific memory T cell responses compared with adults. This agreed with our TCR sequencing data showing reduced clonal expansion in children. A strong stem cell memory phenotype and common T cell receptor motifs were detected within tetramer-specific T cells in seroconverted children. Conversely, children who did not seroconvert had tetramer-specific T cells of predominantly naive phenotypes and diverse TCRαβ repertoires. Our study demonstrates the generation of SARS-CoV-2-specific T cell memory with common TCRαβ motifs in unvaccinated seroconverted children after their first virus encounter.
Keywords: B cells; CD4(+) T cells; CD8(+) T cells; COVID-19; SARS-CoV-2; children; memory T cells; tetramer-specific.
【저자키워드】 COVID-19, SARS-CoV-2, children, B cells, memory T cells, CD8(+) T cells, CD4(+) T cells, tetramer-specific., 【초록키워드】 coronavirus, vaccination, T cells, B cells, severe acute respiratory syndrome Coronavirus, virus, CD4, CD8, memory, Adults, Epitopes, T cell, response, phenotype, respiratory, convalescent, T cell receptor, memory T cell, SARS-CoV-2 epitopes, HLA class I, TCR sequencing, stem cell, clonal expansion, Ex vivo, acute respiratory syndrome, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, ORF1a, circulating, seroconvert, T cell memory, motif, memory T, tetramer, Cell, Seven, analyzed, recruited, reduced, seroconverted, comparable, to define, presenting, 【제목키워드】 Infection, seroconvert, T cell memory, motif,