Abstract
The emergence of SARS-CoV-2 variants harboring mutations in the spike (S) protein has raised concern about potential immune escape. Here, we studied humoral and cellular immune responses to wild type SARS-CoV-2 and the B.1.1.7 and B.1.351 variants of concern in a cohort of 121 BNT162b2 mRNA-vaccinated health care workers (HCW). Twenty-three HCW recovered from mild COVID-19 disease and exhibited a recall response with high levels of SARS-CoV-2-specific functional antibodies and virus-specific T cells after a single vaccination. Specific immune responses were also detected in seronegative HCW after one vaccination, but a second dose was required to reach high levels of functional antibodies and cellular immune responses in all individuals. Vaccination-induced antibodies cross-neutralized the variants B.1.1.7 and B.1.351, but the neutralizing capacity and Fc-mediated functionality against B.1.351 was consistently 2- to 4-fold lower than to the homologous virus. In addition, peripheral blood mononuclear cells were stimulated with peptide pools spanning the mutated S regions of B.1.1.7 and B.1.351 to detect cross-reactivity of SARS-CoV-2-specific T cells with variants. Importantly, we observed no differences in CD4 + T-cell activation in response to variant antigens, indicating that the B.1.1.7 and B.1.351 S proteins do not escape T-cell-mediated immunity elicited by the wild type S protein. In conclusion, this study shows that some variants can partially escape humoral immunity induced by SARS-CoV-2 infection or BNT162b2 vaccination, but S-specific CD4 + T-cell activation is not affected by the mutations in the B.1.1.7 and B.1.351 variants.
【초록키워드】 SARS-CoV-2, immune response, vaccination, Mutation, Health care, S protein, antibody, B.1.351, Cellular immune response, T cells, SARS-COV-2 infection, variant, SARS-CoV-2 variant, peptide, virus, CD4, variants, COVID-19 disease, Peripheral blood, cross-reactivity, BNT162b2, Protein, Humoral immunity, Cohort, Region, Immune escape, SARS-CoV-2 variants, B.1.1.7, immune responses, Peripheral blood mononuclear cells, Health care worker, Mild, antigens, neutralizing capacity, recall, homologous, wild type, seronegative, SARS-CoV-2-specific T cells, Humoral and cellular immune responses, B.1.351 variants, humoral, HCW, mononuclear cells, mononuclear cell, B.1.351 variant, second dose, no difference, no differences, S proteins, Mild COVID-19 disease, cellular immune responses, T-cell activation, Specific, peptide pools, single vaccination, T-cell-mediated immunity, stimulated, detect, addition, raised, required, exhibited, functional, mutated, individuals, not affected, elicited, virus-specific T cell, peptide pool, SARS-CoV-2-specific T cell, 【제목키워드】 T-cell Response, SARS-CoV-2 variant, humoral, vaccinee, COVID-19 convalescent donor,