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Emerg Microbes Infect . The third dose of CoronVac vaccination induces broad and potent adaptive immune responses that recognize SARS-CoV-2 Delta an

tetano

Editor, Senior Moderator
Emerg Microbes Infect


. 2022 May 24;1-44.
doi: 10.1080/22221751.2022.2081614. Online ahead of print.
The third dose of CoronVac vaccination induces broad and potent adaptive immune responses that recognize SARS-CoV-2 Delta and Omicron variants


Yuxin Chen[SUP] 1 2 [/SUP], Lin Chen[SUP] 3 [/SUP], Shengxia Yin[SUP] 2 4 [/SUP], Yue Tao[SUP] 3 [/SUP], Liguo Zhu[SUP] 5 [/SUP], Xin Tong[SUP] 2 4 [/SUP], Minxin Mao[SUP] 4 [/SUP], Ming Li[SUP] 4 [/SUP], Yawen Wan[SUP] 4 [/SUP], Jun Ni[SUP] 1 [/SUP], Xiaoyun Ji[SUP] 2 6 [/SUP], Xianchi Dong[SUP] 7 [/SUP], Jie Li[SUP] 2 4 [/SUP], Rui Huang[SUP] 2 4 [/SUP], Ya Shen[SUP] 5 [/SUP], Han Shen[SUP] 1 [/SUP], Changjun Bao[SUP] 5 [/SUP], Chao Wu[SUP] 1 2 [/SUP]



Affiliations

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 was 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[SUP]+[/SUP] and CD8[SUP]+[/SUP] T cells peaked and sustained after the booster. Notably, CD4[SUP]+[/SUP] and CD8[SUP]+[/SUP] 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[SUP]+[/SUP] and CD8[SUP]+[/SUP] 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; CoronaVac; T cell responses; booster; neutralization.
 
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