Fig. 7: SARS-CoV-2 infection induces germinal center responses in mediastinal lymph nodes.
From: SARS-CoV-2 induces robust germinal center CD4 T follicular helper cell responses in rhesus macaques
A Representative multi-color immunofluorescence image of CD3, PD-1, CD20, Bcl-6 with DAPI staining in mediastinal lymph nodes. Two connecting sections were stained with CD3/PD-1 and CD20/ Bcl-6/CD3 to visualize germinal center (GC) Tfh cells and GC B cells, respectively. Images in (a–d) showing GC B cells and images in (f–i) showing GC Tfh cells are enlarged from white boxes in (e) and collected using a ×20 objective. Merged image in (d) shows CD20+Bcl-6+ GC B cells and image in (i) shows CD3 + PD-1+ GC Tfh cells. Scale bar in (e) is 100 µm and the rest are 25 µm. CD3 stain in pink is pseudo color (original red) to distinguish from Bcl-6. B Representative gating strategy to identify follicular dendritic cells (FDC), germinal center B cells (GC B), and germinal center Tfh cells (GC Tfh) in the mediastinal lymph nodes (Med) Fluorochromes used were CD45-A488, CD3-A700, CD20-BV421, Dead-BV510, CD8-BUV 805, CD4-BV650, CD95-BUV737, CXCR5-PE, PD-1-Pe-Cy7, Bcl-6-APC-Cy7, CD140b-APC, CD21-PECF594, CXCR3-BV786. C Median fluorescence intensity of Bcl-6, CD21, CD140b, and CXCR3. D Frequency of GC Tfh cells, GC B cells, FDCs significantly higher in mediastinal lymph node (Med, data shown from n = 8 independent animals (GC Tfh; **p = 0.007, *p = 0.01) relative to cervical lymph nodes (CLN, data shown from n = 8 independent animals) and mesenteric lymph nodes (Mes, data shown from n = 7 independent animals) using a two-tailed Wilcoxon matched-pairs signed-rank test, GC B cells; *p = 0.04 using a two-tailed Wilcoxon matched-pairs signed-rank test, FDCs; p = 0.039 using a two-tailed Wilcoxon matched-pairs signed-rank test. Horizontal line indicates median. E Majority of GC Tfh cells in mediastinal lymph nodes express CXCR3 (GC Tfh and Tfh; **p = 0.007, *p = 0.01, and mTfh *p = 0.01 relative to CLN and Mes using a two-tailed Wilcoxon matched-pairs signed-rank test). Data shown are from n = 8 independent animals for Med, CLN, and n = 7 independent animals for Mes. Horizontal line indicates median.
