REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
Rabbit anti human FV	Abcam	Cat#ab234849
Mouse anti human CD45	Agilent DAKO	Cat#M070101-2, Clones 2B11 + PD7/26; RRID:AB_2750582
Mouse anti human Elastase	R&D systems	Cat#MAB91671, Clone 950317
Mouse anti human CD68	Abcam	Cat#ab199000, Clones KP1 + C68/684
Mouse anti human CD3	Abcam	Cat#ab17143, Clone F7.2.38; RRID:AB_782094
Mouse anti human cytokeratin	Abcam	Cat#ab27988, Clone AE1/AE3; RRID:AB_10717335
Biological samples
Covid patient lung tissue	Cambridge University Hospital Tissue Bank, https://www.cuh.nhs.uk/our-research/research-facilities/tissue-bank	Cat#G14678
Chemicals, peptides, and recombinant proteins
Native human FV	Invitrogen	Cat#RP-43126
Native human FVa	Invitrogen	Cat#RP-43100
Thrombin	Invitrogen	Cat#RP-43128
Hirudin	Sigma-Aldrich	H0393; CAS:8001-27-2
Recombinant FV B domain (aa710-1545)	Peak Proteins	http://peakproteins.com
Recombinant FV (aa 1 - 2224)	Peak Proteins	http://peakproteins.com
Recombinant FV (aa 1 - 2224) [R709A, R1018A, R1545A]	Peak Proteins	http://peakproteins.com
Critical commercial assays
CFSE labeling kit	Invitrogen	Cat#C34554
FV ELISA kit	Abcam	Cat#137976
Human B cell expansion kit	R&D system	Cat#CDK005
CD4 Tcell isolation kit	Miltenyi	Cat#130-091-301
CD8 MicroBeads	Miltenyi	Cat#130-045-201
Pan B cell isolation kit	Miltenyi	Cat#130-101-638
Deposited data
Whole blood RNAseq data	Bergamaschi et al., 2021, https://doi.org/10.1016/j.immuni.2021.05.010, and this paper	https://ega-archive.org/search-results.php?query=EGAS00001005332
scRNAseq data	Stephenson et al., 2021, https://doi.org/10.1038/s41591-021-01329-2, and this paper	https://www.ebi.ac.uk/arrayexpress/experiments/E-MTAB-10026/
Clinical and demographic data	Bergamaschi et al., 2021, https://doi.org/10.1016/j.immuni.2021.05.010, and this paper	Table S1: Clinical features of study participants, stratified by group A-E; https://ars.els-cdn.com/content/image/1-s2.0-S1074761321002168-mmc1.pdfhttps://www.covid19cellatlas.org/patient/citiid/
Experimental models: Cell lines
Human CD4+ T cells	NHS blood and transplant service	https://www.nhsbt.nhs.uk/
Human CD8+ T cells	NHS blood and transplant service	https://www.nhsbt.nhs.uk/
Human B cells	NHS blood and transplant service	https://www.nhsbt.nhs.uk/
Software and algorithms
R	R Core Team, 2015	N/A
Flowjo_v10.0.8	BD Biosciences	https://www.flowjo.com/
GraphPad Prism 9	Dr. Harvey Motulsky	https://www.graphpad.com/scientific-software/prism/
Gene set enrichment analysis (GSEA)	Broad Institute	https://www.gsea-msigdb.org/gsea/index.jsp
GO enrichment analysis	Gene ontology consortium	http://geneontology.org/docs/go-enrichment-analysis/
Enrichr	Ma’ayan lab	https://maayanlab.cloud/Enrichr/#about
FastQC v.0.11.8	Babraham Bioinformatics, UK	https://www.bioinformatics.babraham.ac.uk/projects/fastqc/
Trim_galore v.0.6.4	Babraham Bioinformatics, UK	https://www.bioinformatics.babraham.ac.uk/projects/trim_galore/
BBMap v.38.67	BBMap - Bushnell B	https://sourceforge.net/projects/bbmap/
Blueprint epigenome	Blueprint consortium	https://www.blueprint-epigenome.eu/
Specronaut 14	Biognosys	https://biognosys.com/software/spectronaut/