Extended Data Fig. 1: Fibrin interaction and colocalization with Spike.
From: Fibrin drives thromboinflammation and neuropathology in COVID-19
a, Binding ELISA of Spike S1(N501Y) to fibrin. Dissociation constants (Kd). Representative curvefits from two independent biological experiments in duplicates. b, Spike overlap with perivascular fibrin(ogen) deposition in lung of Beta-infected WT mice at 3 d.p.i. The 51% of the calculated proportion of fibrin that colocalizes with Spike protein is significantly higher than the 23% predicted if the correlation were random. Fisher’s exact test (two-tailed); n = 78 images from 5 mice (Methods). Representative confocal images are shown. Scale bar, 200 μm. c, Scatter plot of positive correlation of fibrinogen and Spike immunoreactivity in n = 78 images from 5 mice, Pearson correlation two-tailed (Methods). d. 3D reconstruction of light sheet acquisitions of whole lung tissue from an Alexa546-fibrinogen and Alexa647-Spike S1(N501Y)-injected WT mouse following 3DISCO tissue clearing. Two representative focal fibrinogen deposits from n = 3 mice were selected for 3D visualization. Volumetric rendering reveals close interactions between fibrinogen deposits (green) and trimeric spike (magenta), confirming colocalization. Scale bars, 100 μm (top), 300 μm (bottom). e, Fibrinogen crystal structure (PDB: 3GHG) with mapped peptides (red). Proximity of peptides γ163-181 and γ364-395 (inset). f, Peptide array mapping with immobilized peptides of SARS-CoV-2 Spike blotted with fibrinogen and fibrinogen γ chain. Heatmap of signal intensity showing binding sites (white-orange) within the S1-NT Spike domain. Key indicates fluorescence intensities signal values from low (white) to high (orange). Schematic indicating Spike domains and amino acid sequence.
