Dynamic SARS-CoV-2-specific B-cell and T-cell responses following immunization with an inactivated COVID-19 vaccine. (March 2022)

• Record Type: Journal Article
• Authors: Chen, Yuxin; Yin, Shengxia; Tong, Xin; Tao, Yue; Ni, Jun; Pan, Jie; Li, Ming; Wan, Yawen; Mao, Minxin; Xiong, Yali; Yan, Xiaomin; Yang, Yue; Huang, Rui; Wu, Chao; Shen, Han
• Is Part Of: Clinical microbiology and infection. Volume 28:Number 3(2022)
• Page Start: 410
• Page End: 418
• Publication Date: 2022-03
• Subjects: Adaptive responses -- B cells -- COVID-19 -- Inactivated virus vaccine -- Neutralization -- T cells; Medical microbiology -- Periodicals; Diagnostic microbiology -- Periodicals; Communicable diseases -- Periodicals; Infection -- Periodicals; 616.01
• DOI: 10.1016/j.cmi.2021.10.006
• Languages: English
• ISSNs: 1198-743X

Abstract

Abstract: Objective: The dynamic adaptive immune responses elicited by the inactivated virus vaccine CoronaVac remain elusive. Methods: In a prospective cohort of 100 healthcare professionals naïve for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) who received two doses of CoronaVac, we analysed SARS-CoV-2-specific humoral and cellular responses at four different timepoints, including before vaccination (T1), 2 weeks after the first dose (T2), 2 weeks after the booster dose (T3), and 8–10 weeks after the booster dose (T4). SARS-CoV-2-specific antibodies, serum neutralizing activities, peripheral B cells, CD4 + and CD8 + T cells and their memory subsets were simultaneously measured in this cohort. Results: SARS-CoV-2 spike-specific IgG responses reached a peak (geometric mean titre (GMT) 54827, 30969–97065) after two doses and rapidly declined (GMT 502, 212–1190) at T4, whereas suboptimal IgA responses were detected (GMT 5, 2–9). Spike-specific circulating B cells (0.60%, 0.46–0.73% of total B cells) and memory B cells (1.18%, 0.92–1.44% of total memory B cells) were effectively induced at T3 and sustained over time (0.33%, 0.23–0.43%; 0.87%, 0.05–1.67%, respectively). SARS-CoV-2-specific circulating CD4 + T cells (0.57%, 0.47–0.66%) and CD8 + T cells (1.29%, 1.04–1.54%) were detected at T3. At T4, 0.78% (0.43–1.20%) of memory CD4+ T cells and 0.68% (0.29–1.30%) of memory CD8+ T cells were identified as SARS-CoV-2-specific, while 0.62% (0.51–0.75%) of CD4 + T cells and 0.47% (0.38–0.58%) of CD8 + T cells were SARS-CoV-2-specific terminally differentiated effector memory cells. Furthermore, age and interval between doses affected the magnitude of CoronaVac-induced immune responses. SARS-CoV-2 memory CD4 + T cells were strongly associated with both receptor binding domain (RBD)-specific memory B cells (r 0.87, p <0.0001) and SARS-CoV-2-specific memory CD8 + T cells (r 0.48, p <0.0001). Conclusions: CoronaVac induced robust circulating and memory B cell and T cell responses. Our study offers new insight into the underlying immunobiology of inactivated virus vaccines in humans and may have implications for vaccine strategies in the future. Graphical abstract: Image 1