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Article
SARS-CoV-2 infection induces robust germinal center CD4 T follicular helper cell responses in rhesus macaques
Smita Iyer
University of California Davis School of Veterinary Medicine and California National Primate Research Center.
Corresponding Author
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CD4 T follicular helper (Tfh) cells are important for the generation of durable and specific humoral protection against viral infections. The degree to which SARS-CoV-2 infection generates Tfh cells and stimulates the germinal center response is an important question as we investigate vaccine options for the current pandemic. Here we report that SARS-CoV-2 infection resulted in transient accumulation of pro-inflammatory monocytes and proliferating Tfh cells with a Th1 profile in peripheral blood. CD4 helper cell responses were skewed predominantly toward a Th1 response in blood, lung, and lymph nodes. We observed the generation of germinal center Tfh cells specific for the SARS-CoV-2 spike (S) and nucleocapsid (N) proteins, and a corresponding early appearance of antiviral serum IgG antibodies. Our data suggest that a vaccine promoting Th1-type Tfh responses that target the S protein may lead to protective immunity.
Keywords
SARS-CoV-2, Adaptive Immunity, Innate Immunity, SARS-CoV-2 specific antibody; SARS-CoV-2 specific T cells, Convalescent plasma, Nucleocapsid, Spike
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- 20200706CoVSupplementarymaterial.docx
Supplementary material
- FigureS1.png
Humoral responses to SARS-CoV-2 are dominated by IgG antibodies Concentrations of (A) IgM, (B) IgG, and (C) IgA antibodies specific for S1, S2, and N proteins measured by BAMA or ELISA in serum. The dashed line represents the median pre-infection (day 0) concentration for all animals. (D) Fold increase in antibody responses in animals not given CP was determined by dividing post-infection concentrations by those measured on day 0 in each animal. Geometric mean fold increases with SEM are shown. (E) Correlations between day 10 levels of S1-specific IgG and IgM, N-specific IgA and IgG, and pseudovirus neutralizing antibody titers and anti-RBD IgG antibodies measured by ELISA. Unique symbols identify animals in each of the experimental groups.
- FigureS2.jpg
SARS-CoV-2 infection elicits Ki67+PD-1+ Th1 cells at Day 7 that are polyfunctional (A) tSNE plots of CD4+Ki-67+PD-1+ CXCR5+/CXCR5- populations show representation of Th1 effectors [CXCR3+], Th2 effectors [CCR4+], and Th17 effectors [CCR6+] (B) Increase of Ki67+PD-1+ Th1 cells in both cell frequency and cells/ul blood at day 7 post infection (C) Kinetics of Ki-67+ PD-1+ Th2 cells [/ul blood] (D) Kinetics of Ki-67+ PD-1+ Th17 cells [/ul blood] (E) Representative expression of IFNg, IL-17, IL-2, TNF-α within two CD4 populations: CD107a/b+ cells and IL-21+ cells after stimulation (F) Serum CXCL13 following infection.
- FigureS3.png
Splenic GC TFH, Tfr, and Treg populations during SARS-CoV-2 infection (A) Flow Plot of splenic GC TFH cells [CXCR5+PD-1hi] at necropsy (d11-d14pi) and dot plot graph designating an increase of GC TFH in SARS-CoV-2 infected rhesus macaques (B) Flow Plot of Treg [CD95+, CXCR5-, Foxp3+] and Tfr [CXCR5+,PD-1++, Foxp3+] cells. Controls (circles) are RM that were infected and received no plasma treatment, Infused (triangles) are RM that were infected and received either convalescent plasma or normal plasma.
- FigureS4.png
SARS-CoV-2 infection increases mediastinal lymph node size and elicits GC Tfh cells. (A) Large aggregate of bronchial associated lymphoid tissue [arrow] adjacent to a moderately large airway and associated blood vessel. Two well defined germinal centers can be seen within the BALT (B) Comparison of SARS-CoV-2 uninfected [left] and SARS-CoV-2 infected [right] Mediastinal lymph nodes show distinct lymphadenopathy (C) Detection of follicular dendritic cells (FDCs) gating on CD45-Lin-CD14-CD35+CD21+ using flow cytometry; three different clones are used for comparison [BL13, BU32, B-LY4] (D) Correlations between % total FDCs and % total GC TFH or % total GC B cells (E) Peptide pool stimulation if mediastinal lymph node cells with Spike (S), Nucleocapsid (N), Membrane protein (M), or PMA/Iono (P/I) show responses in CXCR5+, CXCR5-, or Naïve CD4 T cell populations.
- TableS1.png
Animal information. Sex, Age, Body weight, treatment, infusion volume, blood donor type, total volume infused, necropsy date, prior treatments and extra notes for all animals on the study.
- TableS2.png
Spleen AIM Assay conditions. N, S, M, ORF (nsp3, nsp4, 3a, 8), or P/I stimulation conditions for each animal on the study.
- TableS3.png
Mediastinal LN AIM Assay conditions. N or S peptide stimulation conditions for mediastinal LN for each animal on the study.
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Article
SARS-CoV-2 infection induces robust germinal center CD4 T follicular helper cell responses in rhesus macaques
Smita Iyer
University of California Davis School of Veterinary Medicine and California National Primate Research Center.
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 14 Aug, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
CD4 T follicular helper (Tfh) cells are important for the generation of durable and specific humoral protection against viral infections. The degree to which SARS-CoV-2 infection generates Tfh cells and stimulates the germinal center response is an important question as we investigate vaccine options for the current pandemic. Here we report that SARS-CoV-2 infection resulted in transient accumulation of pro-inflammatory monocytes and proliferating Tfh cells with a Th1 profile in peripheral blood. CD4 helper cell responses were skewed predominantly toward a Th1 response in blood, lung, and lymph nodes. We observed the generation of germinal center Tfh cells specific for the SARS-CoV-2 spike (S) and nucleocapsid (N) proteins, and a corresponding early appearance of antiviral serum IgG antibodies. Our data suggest that a vaccine promoting Th1-type Tfh responses that target the S protein may lead to protective immunity.
Figure 1
Figure 2
Figure 3
Figure 4