Broad cross neutralizing antibodies against sarbecoviruses generated by SARS-CoV-2 infection and vaccination in humans

Figures

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  Fig. 1. SARS-CoV-2 infection and vaccination elicit broad cross-nAb responses against zoonotic sarbecoviruses. A Schematic diagram of participant demographics and baseline characteristics for cross-sectional blood samples, including the number, age, and percentage of sexes of individuals (left panel), as well as an amino acid (aa) alignment of spike proteins for selected sarbecoviruses, comparing identities against SARS-CoV-2. GenBank accession numbers are given for the selected viruses. (right panel). This figure was created with Biorender.com. B, C Endpoint titers of serum IgG antibodies from 73 COVID-19 convalescents (B) and 89 vaccinees (C), determined by antibody binding to sarbecovirus spike S1 (left) and S2 (right) protein subunits. The dashed lines represent the cut-off values (endpoint titer = 400), and a value of endpoint titer > 400 was considered positive for binding. D, E Neutralization titers of plasma samples from 73 COVID-19 convalescents (D) and 89 vaccinees (E) against sarbecovirus pseudotyped viruses. The dashed lines represent the cut-off values (ID50 = 30), and a value of ID50 > 30 was considered positive for neutralization. Data are representative of technical…

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  Fig. 2. Breadth of the cross-neutralization response against sarbecovirus is associated with the potency of the antibody response. A The neutralization breadths of convalescent (left panel) and vaccinee (right panel) plasma samples against eight sarbecoviruses are defined by the range of breadth from 0 to 8. B Correlations between neutralization breadths and neutralization titers against sarbecoviruses in convalescents (left) and vaccinees (right). Spearman’s rank correlation coefficient was employed to assess the association between the neutralization breadth and neutralization titers. P < 0.05 was considered statistically significant using a two-tailed test.

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  Fig. 3. Administration of a vaccine booster significantly augments cross-nAb potency and breadth against sarbecovirus. A Percentage of plasma samples with neutralizing effects against sarbecovirus-pseudotyped virus. The plasma samples were obtained from 25 COVID-19 convalescents before and after vaccination (upper panel) and 25 vaccinees before and after receiving a third booster dose (lower panel). A value of ID50 > 30 was considered positive for neutralization. B Neutralization titers against sarbecovirus-pseudotyped virus for 25 COVID-19 convalescents before and after vaccination (upper panel) and for 25 vaccinees before and after receiving a third booster dose (lower panel). Paired t-tests were employed to examine the differences in neutralization titers pre- and post-vaccination for COVID-19 convalescents and pre- and post-booster vaccination for vaccinees. Significance levels are denoted as follows: *P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. A two-tailed test with P < 0.05 was considered statistically significant. ns, no significant. C Neutralization breadth for COVID-19 convalescents before and after vaccination (upper panel) and for vaccinees before and after…

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  Fig. 4. Isolation and characterization of cross-neutralizing antibodies to sarbecoviruses. A Schematic diagram of the antibody source and quantity (left). Based on spike-binding assays, 370 mAbs were categorized into five types: S1-binding mAbs (red in pie charts), S2-binding mAbs (blue), S1- and S2-binding mAbs (green), extracellular domain of the spike protein (S-ECD) but not S1- and S2-binding mAbs (pink), and no binding (gray). The percentages of neutralizing (red) and non-neutralizing (gray) mAbs were evaluated by SARS-CoV-2 pseudotyped particle assays at an antibody concentration of 10 μg/mL. B–D The gene region usage, CDR3 lengths, and SHM were analyzed for 116 nAbs using IgBLAST. Pie chart showing the germline gene region usage of these nAbs. The five gene regions most used by heavy (left) and light (right) chains are given (B). Distributions of H-CDR3 and L-CDR3 length over a total of 116 nAbs (C). Percent identities of heavy and light chains to the inferred germline among 116 nAbs. Data are presented as medians ± IQRs (25–75%), and the error bars indicate the medians with IQRs (D). E Comparison of the lengths of H-CDR3 (left) and L-CDR3 (right) for nAbs from four distinct…

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  Fig. 5. The mAbs isolated from COVID-19 convalescents and vaccinees exhibit broad neutralizing profiles against sarbecoviruses. A RBD-binding, ACE2 competition, and spike-binding EC50 values were determined for 33 nAbs by ELISA and are presented as a heatmap. Binding was defined as an OD450 value three-fold greater than the cut-off value (i.e., the average OD450 value of negative antibody) at an antibody concentration of 1 μg/mL; ACE2 competition was defined as an antibody binding to the RBD and inhibiting ACE2 binding by > 50%. B Neutralization curves for six nAbs are presented as the percentage of neutralization for pseudotyped sarbecoviruses. Data are representative of technical triplicates. A broad nAb S309 and an unrelated antibody HNC5 were used as the positive and negative controls, respectively. C Neutralization activity (IC50) levels of six nAbs against sarbecoviruses are presented as a heatmap, with darker colors indicating greater levels of neutralization activity. Data are derived from (B). D The binding affinities (KD) of six nAbs for SARS-CoV-1 and SARS-CoV-2 RBD proteins. mAbs were bound to the proA biosensor and then tested for binding to SARS-CoV-1 or SARS-CoV-2 RBD…