REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
CR3022	(ter Meulen et al., 2006)	N/A
S309	(Pinto et al., 2020)	N/A
B38	(Wu et al., 2020)	N/A
Goat anti-human HRP	Invitrogen	Cat #A18817 Lot #65-180-071919
Goat anti-mouse HRP	Invitrogen	Cat #626520 Lot #TG275230
Horse anti-mouse HRP	Cell Signaling Technology	Cat #7076S
Anti-mouse Fc Block	BD Biosciences	Cat#553142 RRID:AB_394657
Anti-mouse B220 BUV737	BD Biosciences	Cat#612838 RRID:AB_2738813
Anti-mouse CD3 PerCP-Cy5.5	BD Biosciences	Cat#551163 RRID:AB_394082
Anti-mouse CD138 BV650	BD Biosciences	Cat#564068 RRID:AB_2738574
Anti-mouse CD38 Alexa Fluor 700	Thermo Fisher Scientific	Cat#56-0381-82 RRID:AB_657740
Anti-mouse GL7 ef450	Thermo Fisher Scientific	Cat#48-5902-82 RRID:AB_10870775
Anti-mouse IgM BV786	BD Biosciences	Cat#743328 RRID:AB_2741429
Anti-mouse IgD BUV395	BD Biosciences	Cat#565988 RRID:AB_2737433
Anti-mouse CD73 PE-Cy7	Thermo Fisher Scientific	Cat#25-0731-82 RRID:AB_10853348
Anti-mouse CD80 BV605	BD Biosciences	Cat#563052 RRID:AB_273795
Biological Samples
BALB/c mice	Jackson Laboratory	Cat#000651
Kymice	Kymab	N/A
20/130 COVID-19 plasma	NIBSC	Sample#20/130
Chemicals, Peptides, and Recombinant Proteins
AddaVax adjuvant	InvivoGen	Cat# vac-adx-10
ABTS	ThermoFisher	Cat# 37615
TMB	SeraCare	Cat# 5120-0083
Thrombin	Sigma	Cat# T9326-150UN
Immobilized Papain	ThermoScientific	Cat# 20341
LysC-endoproteinase	NEB	Cat# P8109S
hACE2-Fc	This study	N/A
EZ-Link Sulfo-NHS-LC Biotinylation Kit	Thermo Fisher Scientific	Cat#21435
Streptavidin-APC	Agilent	Cat#PJ27S-1
Streptavidin-PE	Agilent	Cat#PJRS25-1
Anti-PE MicroBeads	Miltenyi Biotec	Cat#130-048-801
Anti-APC MicroBeads	Miltenyi Biotec	Cat#130-090-855
DyLight 755 Antibody Labeling Kit	Thermo Fisher Scientific	Cat#84538
AlexaFluor 647 Protein Labeling Kit	Thermo Fisher Scientific	Cat#A20173
Experimental Models: Cell Lines
Expi 293F	ThermoFisher	Cat #A14527
Vero(C1008)E6 adherent	ECACC General Collection	Cat #85020206
HEK-ACE2 adherent	BEI (Gift from Bloom lab)	Sample#NR-52511
HEK293T/17 Adherent	ATCC	Cat# CRL-11268
Vero E6	ATCC	Cat# CRL-1586
Recombinant DNA
pCMV-RBD-12GS-50A	GenScript (this study)	N/A
pCMVR-RBD-16GS-50A	GenScript (this study)	N/A
pCMV-RBD-8GS-50A	GenScript (this study)	N/A
S-2P trimer	GenScript (Walls et al., 2020)	Vector# BEI NR-52421
RBD	GenScript (Walls et al., 2020)	Vector# BEI NR-52422
SARS-CoV-2 S full length	GenScript (Walls et al., 2020)	Vector# BEI NR-52420
Murine leukemia virus gag-pol	Millet and Whittaker 2016	N/A
pTG-Luciferase	Millet and Whittaker 2016	N/A
Software and Algorithms
UCSF ChimeraX	(Goddard et al., 2018)	https://www.rbvi.ucsf.edu/chimerax/
Prism	Graphpad	https://www.graphpad.com/scientific-software/prism/
FlowJo v10	FlowJo	https://www.flowjo.com
Other
Octet Biosensors: protein A	Sartorius (FortéBio)	Cat# 18-5010
Octet Biosensors: Anti-Penta-HIS (HIS1K)	Sartorius (FortéBio)	Cat# 18-5120
Octet Biosensors: NTA	Sartorius (FortéBio)	Cat# 18-5101
EM supplies 300 mesh grids	Ted Pella	Cat# 01843-F
Filter paper	Cytiva	Cat# 1004047
Uranyl formate	SPI Chem	Cat# 02545-AA
Unis Capillary Cassettes	Unchained Labs	Cat# 201-1010
PrismA Protein A resin	Cytiva	Cat# 17549802
Superdex 200 Increase SEC column	Cytiva	Cat# 28-9909-44
Superose 6 Increase SEC column	Cytiva	Cat# 29091596
Talon resin	TaKaRa	Cat# 635652
VL26 Vantage L column	Millipore	Cat# 96100250
Excel resin	Cytiva	Cat# 17371203
Patterson Veterinary, Isoflurane, USP	Patterson	Cat# 07-893-1389
Eppendorf(R) Safe-Lock microcentrifuge tubes 1.5-mL	Sigma Millipore	Cat# T9661
BD Luer-Lok™ 1-mL Syringe	BD	Cat# BD309628
BD Single Use Needles 25G x 7/8	VWR	Cat# BD305124
BD PrecisionGlide™ Needle 23Gx1 1/4	BD	Ref# 305120
BD Single Use Needles 27G x 1 1/4	VWR	Cat# BD305136
EndoSafe LAL Test Cartridges	Charles River Labs	Cat # PTS20005F
Lemo21(DE3)	New England BioLabs	Cat#C2528J
Isopropyl-B-D-thiogalactoside (IPTG)	Sigma Aldrich	Cat#I6758
Kanamycin Sulfate	Sigma-Aldrich	Cat#K1876
HiLoad S200 pg	Cytiva	Cat#28989336
Ni Sepharose 6 FF	Cytiva	Cat#17531808
HisTrap FF	Cytiva	Cat#17525501