Abstract
The waning humoral immunity and emerging contagious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants resulted in the necessity of the booster vaccination of coronavirus disease 2019 (COVID-19). The inactivated vaccine, CoronaVac, is the most widely supplied COVID-19 vaccine globally. Whether the CoronaVac booster elicited adaptive responses that cross-recognize SARS-CoV-2 variants of concern (VoCs) among 77 healthy subjects receiving the third dose of CoronaVac were explored. After the boost, remarkable elevated spike-specific IgG and IgA responses, as well as boosted neutralization activities, were observed, despite 3.0-fold and 5.9-fold reduced neutralization activities against Delta and Omicron strains compared to that of the ancestral strain. Furthermore, the booster dose induced potent B cells and memory B cells that cross-bound receptor-binding domain (RBD) proteins derived from VoCs, while Delta and Omicron RBD-specific memory B cell recognitions were reduced by 2.7-fold and 4.2-fold compared to that of ancestral strain, respectively. Consistently, spike-specific circulating follicular helper T cells (cTfh) significantly increased and remained stable after the boost, with a predominant expansion towards cTfh17 subpopulations. Moreover, SARS-CoV-2-specific CD4 + and CD8 + T cells peaked and sustained after the booster. Notably, CD4 + and CD8 + T cell recognition of VoC spike was largely preserved compared to the ancestral strain. Individuals without generating Delta or Omicron neutralization activities had comparable levels of CD4 + and CD8 + T cells responses as those with detectable neutralizing activities. Our study demonstrated that the CoronaVac booster induced broad and potent adaptive immune responses that could be effective in controlling SARS-CoV-2 Delta and Omicron variants.
Keywords: COVID-19 vaccine; T cell responses; booster; coronavac; neutralization.
【저자키워드】 COVID-19 vaccine, CoronaVac, T cell responses, booster, neutralization., 【초록키워드】 COVID-19, coronavirus disease, SARS-CoV-2, Coronavirus disease 2019, coronavirus, adaptive, T cells, neutralization, variant, SARS-CoV-2 variant, B cells, CoronaVac, memory B cells, Delta, omicron, CD4, CD8, Omicron variants, variants, B cell, Protein, Humoral immunity, T cell, Inactivated vaccine, RBD, immune responses, response, VOCs, Adaptive immune response, respiratory, booster dose, booster, boost, memory B cell, booster vaccination, dose, strain, T cells response, acute respiratory syndrome, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, individual, domain, neutralization activity, fold, circulating, neutralization activities, neutralizing activities, contagious, IgA responses, subpopulations, spike-specific IgG, SARS-CoV-2 delta, effective, Cell, helper T cell, memory B, significantly increased, peaked, remained, detectable, elevated, receiving, reduced, demonstrated, comparable, predominant, elicited, sustained, healthy subject, follicular, preserved, 【제목키워드】 SARS-CoV-2, vaccination, variant, Delta, omicron, Adaptive immune response, dose, recognize, induce,