Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea.
Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, South Korea.
Department of Anatomy & Cell Biology, Seoul National University College of Medicine, Seoul, South Korea.
BrainKorea21 (BK21) FOUR Biomedical Science Project, Seoul National University College of Medicine, Seoul, South Korea.
Department of Pharmacology, Seoul National University College of Medicine, Seoul, South Korea.
Department of Microbiology, School of Medicine, Gachon University, Incheon, South Korea.
Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, South Korea.
BrainKorea21 (BK21) Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea.
College of Pharmacy, Korea University, Sejong, South Korea.
Medical Research Institute, Seoul National University College of Medicine, Seoul, South Korea.
Wide River Institute of Immunology, Seoul National University, Hongcheon, South Korea.
Abstract
BACKGROUND Despite the fact of ongoing worldwide vaccination programs for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), understanding longevity, breadth, and type of immune response to coronavirus disease-19 (COVID-19) is still important to optimize the vaccination strategy and estimate the risk of reinfection. Therefore, we performed thorough immunological assessments 1 year post-COVID-19 with different severity.
METHODS We analyzed peripheral blood mononuclear cells and plasma samples at 1 year post-COVID-19 in patients who experienced asymptomatic, mild, and severe illness to assess titers of various isotypes of antibodies (Abs) against SARS-CoV-2 antigens, phagocytic capability, and memory B- and T-cell responses.
FINDINGS A total of 24 patients (7, 9, and 8 asymptomatic, mild, and severe patients, respectively) and eight healthy volunteers were included in this study. We firstly showed that disease severity is correlated with parameters of immune responses at 1 year post-COVID-19 that play an important role in protecting against reinfection with SARS-CoV-2, namely, the phagocytic capacity of Abs and memory B-cell responses.
INTERPRETATION Various immune responses at 1 year post-COVID-19, particularly the phagocytic capacity and memory B-cell responses, were dependent on the severity of the prior COVID-19. Our data could provide a clue for a tailored vaccination strategy after natural infection according to the severity of COVID-19.
SARS-CoV-2antibodymemory B cellsmemory T cellsphagocytosis
Figures
Graphical AbstractFigure 1Longitudinal analysis of anti-SARS-CoV-2 antibody in COVID-19 patients over time according to the severity of illness. (A) Schematic illustration (created with BioRender.com) of experimental design for analyzing humoral and cellular immune response to SARS-CoV-2 according to the disease severity, including Figures 1–4. (B) Binding activities of each Ig isotype to SARS-CoV-2 proteins. Diluted plasma samples (1:100) in PBS were incubated with SARS-CoV-2 spike protein, receptor-binding domain (RBD), nucleocapsid (NC), and M protein. Corresponding isotyping Abs determined binding activities of IgM, IgA, and IgG to SARS-CoV-2 antigens. ASx, asymptomatic (8-month: n = 7, 12-month: n = 6), Mild (8-month: n = 2, 12-month: n = 9), Severe (8-month: n = 7, 12-month: n = 8). Statistical analyses were performed using the Kruskal–Wallis rank-sum test with Dunn’s post hoc test in GraphPad Prism (n.s.: P >0.05, *P <0.05, **P <0.01, ***P <0.001).Figure 2In vitro phagocytic capability assays according to the severity of illness. ADCP assays with THP-1 cells as effectors and RBD-coated fluorescent, carboxylate-modified 1 μm red (580/605 nm, F8821) bead as targets (effector: target ratio of 10:1). RBD-coated red beads were pre-incubated with the diluted plasma for 20 min and then incubated with THP-1 cells for 2 h. Phagocytic activities were determined by flow cytometric analysis. % of Phagocytosis = numbers of red (580/605 nm) − positive THP-1 cells/numbers of total THP-1 cells × 100. Results are representative data from three independent experiments. Statistical analysis was performed using the Kruskal–Wallis rank-sum test with Dunn’s post hoc test in GraphPad Prism (n.s.: P >0.05, **P <0.01).Figure 3Memory B-cell responses against SARS-CoV-2 according to the severity of illness. (A, C, E) Representative gating strategy for IgM+, IgA+, and IgG+ antigen-specific memory (CD27+ CD19+) B cells. (B, D, F) Frequencies of IgM+, IgA+, and IgG+ antigen-specific memory B cells according to the severity of illness and different antigens. Statistical analysis was performed using the Kruskal–Wallis rank-sum test with Dunn’s post hoc test in GraphPad Prism (n.s.: P >0.05, *P <0.05, **P <0.01, ***P <0.001).Figure 4Frequencies of SARS-CoV-2-specific activation-induced markers (AIM)+ CD4+ or CD8+ T cells according to the severity of illness. (A) Frequencies of SARS-CoV-2-specific AIM+ (OX40+CD137+) CD4+ T cells according to the severity of illness. (B) Frequencies of SARS-CoV-2-specific AIM+ (CD69+CD137+) CD8+ T cells according to the severity of illness. Statistical analyses were performed using the Kruskal-Wallis rank-sum test with Dunn’s post hoc test in GraphPad Prism (n.s. : P > 0.05, *P < 0.05, **P < 0.01).Figure 5Integrated analysis of immune components to SARS-CoV-2 according to the severity. (A) Principal component analysis (PCA) of aggregated immune responses data against SARS-CoV-2, namely, circulating Abs against SARS-CoV-2 proteins, the Ab-dependent phagocytic capability of plasma, and frequencies of antigen-specific memory cells over disease severity of illness from PBMCs collected at 12 months in patients and healthy subject. HC (2021): healthy control (n = 5), ASx: asymptomatic (n = 4), Mild (n = 6), Severe (n = 7). (B) Summary boxplots of PC-1 and PC-2 scores over disease severity of illness. Statistics were calculated using non-parametric ANOVA with correction for multiple comparisons using statistical hypothesis testing (Dunn’s test) (n.s.: P >0.05, *P <0.05, **P <0.01, ***P <0.001). Boxplots represent median with interquartile range. (C) Correlations of antigen-specific immune responses against the PC-1 and PC-2, displaying contributions of 47 immune components to PC-1 and PC-2 in group comparisons. The color represents Spearman’s rank correlation coefficient (ρ); red color indicates positive correlations, and blue indicates negative correlations among patient groups of disease severity. Statistics were adjusted using Bonferroni correction in the consideration of multiple statistical hypothesis n.s.: adj. P >0.05, * adj. P < 0.05, ** adj. P < 0.01, *** adj. P < 0.005, **** adj. P < 0.001. (D) Representative scatter plots displaying the relative levels of selected features onto PC space. The color represents z-score of each feature according to heat scale ranges from purple (low) to yellowish brown (high) color. PC-1, principal component-1; PC-2, principal component-2; mem B, memory B cells.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
그 밖의 정보
출판 형태
Journal Article, Research Support, Non-U.S. Gov't
저널
Frontiers in immunology · eISSN 1664-3224
전자 출판
2022-03-21
MeSH
Antibodies, Viral · COVID-19* · Humans · Immunity · Leukocytes, Mononuclear · Reinfection · SARS-CoV-2 · Severity of Illness Index
