Frontiers in Immunology (Dec 2021)

Characterization of SARS-CoV-2-Specific Humoral and Cellular Immune Responses Induced by Inactivated COVID-19 Vaccines in a Real-World Setting

  • Ziwei Li,
  • Ziwei Li,
  • Tiandan Xiang,
  • Tiandan Xiang,
  • Boyun Liang,
  • Boyun Liang,
  • Hui Deng,
  • Hui Deng,
  • Hua Wang,
  • Hua Wang,
  • Xuemei Feng,
  • Xuemei Feng,
  • Xufeng Quan,
  • Xufeng Quan,
  • Xiaoyan Wang,
  • Xiaoyan Wang,
  • Sumeng Li,
  • Sumeng Li,
  • Sihong Lu,
  • Sihong Lu,
  • Xuecheng Yang,
  • Xuecheng Yang,
  • Baoju Wang,
  • Baoju Wang,
  • Gennadiy Zelinskyy,
  • Gennadiy Zelinskyy,
  • Mirko Trilling,
  • Mirko Trilling,
  • Kathrin Sutter,
  • Kathrin Sutter,
  • Mengji Lu,
  • Mengji Lu,
  • Ulf Dittmer,
  • Ulf Dittmer,
  • Dongliang Yang,
  • Dongliang Yang,
  • Xin Zheng,
  • Xin Zheng,
  • Jia Liu,
  • Jia Liu

DOI
https://doi.org/10.3389/fimmu.2021.802858
Journal volume & issue
Vol. 12

Abstract

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While the immunogenicity of inactivated vaccines against coronavirus disease 2019 (COVID‐19) has been characterized in several well-conducted clinical trials, real-world evidence concerning immune responses against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) raised by such vaccines is currently missing. Here, we comprehensively characterized various parameters of SARS-CoV-2-specific cellular and humoral immune responses induced by inactivated COVID-19 vaccines in 126 individuals under real-world conditions. After two doses of vaccination, S-receptor binding domain IgG (S-RBD IgG) and neutralizing antibody (NAb) were detected in 87.06% (74/85) and 78.82% (67/85) of individuals, respectively. Female participants developed higher concentrations of S-RBD IgG and NAb compared to male vaccinees. Interestingly, a longer dosing interval between the first and second vaccination resulted in a better long-term SARS-CoV-2 S-RBD IgG response. The frequencies of CD4+ T cells that produce effector cytokines (IFN-γ, IL-2, and TNF-α) in response to stimulation with peptide pools corresponding to the SARS-CoV-2 spike (S), nucleocapsid (N) or membrane (M) protein were significantly higher in individuals received two doses of vaccine than those received one dose of vaccine and unvaccinated individuals. S, N, or M-specific CD4+ and CD8+ T cell responses were detectable in 95.83% (69/72) and 54.16% (39/72) of double-vaccinated individuals, respectively. The longitudinal analysis demonstrated that CD4+ T cell responses recognizing S, N, and M waned quickly after a single vaccine dose, but were boosted and became more sustained following a second dose. Overall, we provide a comprehensive characterization of immune responses induced by inactivated COVID-19 vaccines in real-world settings, suggesting that both humoral and cellular SARS-CoV-2-specific immunity are elicited in the majority of individuals after two doses of inactivated COVID-19 vaccines.

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