REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
Anti-mouse B220-BV711	BDBiosciences	Cat# 563892
Anti-mouse-CD19- APC-R700	BDBiosciences	Cat# 565473
Goat F(ab')2 Anti-Mouse IgM	Southern Biotech	Cat# 1022-01
Anti-IgD BV510	BDBiosciences	Cat# 563110
Anti-IgM PE-Cy7	BDBiosciences	Cat# 552867
Anti-IgG1-FITC	BDBiosciences	Cat# 553443
Anti-IgG2a/2b-FITC	BDBiosciences	Cat# 553399
Anti-IgG3-FITC	BDBiosciences	Cat# 553403
Anti-Fas-BV605	BDBiosciences	Cat#740367
Anti-CD38-PEcy5	eBioscience	Cat# 15-0381-82
Goat Anti-Human IgG (HRP)	SeraCare	Cat# 5220-0277
Bacterial and virus strains
Chemically competent DH5αEscherichia coli	Thermo Fisher Scientific	Cat#: 12879416
Biological samples
Mouse sera, immunized	This study	N/A
Chemicals, peptides, and recombinant proteins
FreeStyle 293F media	Thermo Fisher Scientific	Cat# 12338026
Opti-MEM Reduced Serum Medium	Thermo Fisher Scientific	Cat# 31985070
PEI MAX transfection reagent	Polysciences	Cat# 24765-1
Lipofectamine 2000	Life Technologies	Cat# 11668-019
Dulbecco’s Modified Eagle Medium	Life Technologies	Cat# 41966052
Acetonitrile, 80%, 20% Water with 0.1% Formic Acid, Optima LC/MS	Fisher Scientific	Cat# 15431423
Water with 0.1% Formic Acid (v/v), Optima LC/MS Grade	Fisher Scientific	Cat# LS118-212
Acetonitrile	Fisher Scientific	Cat# 10489553
Trifluoroacetic acid	Fisher Scientific	Cat# 10155347
Procainamide hydrochloride	Abcam	Cat# ab120955
H2O18	Sigma-Aldrich	Cat# 329878
Dithiothreitol	Sigma-Aldrich	Cat# 43819
Iodacetamide	Sigma-Aldrich	Cat# I1149
Ammonium formate buffer	Waters	Cat# 186007081
Sodium cyanoborohydride	Sigma-Aldrich	Cat# 156159
DMSO	Sigma-Aldrich	Cat# D2438
Acetic acid	Fisher Scientific	Cat# 10384970
Peptide-N-glycosidase F	New England Biolabs	Cat# P0705S
Endoglycosidase H	New England Biolabs	Cat# P0702S
Mass spectrometry grade trypsin	Promega	Cat# V5280
Sequencing grade chymotrypsin	Promega	Cat# V1061
HBS-EP buffer	Cytiva	Cat# BR100188
Sensor Chips, CM5	Cytiva	Cat# 29149604
Aqueous buffer, 10mM Glycine-HCl pH2.0	Cytiva	Cat# BR100355
Penicillin	Sigma-Aldrich	P3032-10MU
Streptomycin	VWR	382-EU-100G
GIBCO DPBS	Life Technologies	Cat# 12559069
Glycyl Glycine 99+%	Fisher Scientific	Cat# 10540771
MgSO4	VWR	Cat# 10034-99-8
TitriPlex III (EDTA)	VWR	Cat# 1.08418.1000
Triton X-100	Fisher Scientific	Cat# BP151500
Tris	Sigma-Aldrich	Cat# 10708976001
HCl	Biosolve	Cat# 084105
Glycine	VWR	Cat# 4500345965
Magnesium Chloride (MgCl2)	VWR	Cat# 4500348228
Sodium Bicarbonate (NaHCO3)	Life Technologies	Cat# 25080094
Sodium Chloride (NaCl)	Sigma-Aldrich	Cat# S7653-1KG
Sodium Acetate (NaAc)	VWR	Cat# 1.06268.1000
Citric Acid Monohydrate	Brunschwig	Cat# 36665.22
3,3′,5,5′-Tetramethylbenzidine (TMB)	Sigma-Aldrich	Cat# T-2885
H2O2	Brunschwig	Cat# CP26.1
Sulfuric Acid 95-97%	VWR	Cat# 1.00731.1010
Sodium Dodecyl Sulfate	Sigma	Cat# L5750-1kg
Glycerol	Thermo Fisher Scientific	Cat# 15514-011
Critical commercial assays
Fluo-4 Direct™ Calcium Assay Kits	Thermo Fisher Scientific	Cat# F10471
MiSeq Reagent Kit v3 (600-cycle)	illumina	MS-102-3003
Deposited data
BG505 GT1.2 in complex with PGT124 and gl-PGV20	This study	PDB 81EP
Next generation sequencing data	This study	NRA: 32312762-32312784
Experimental models: Cell lines
HEK293F cells	ThermoFisher Scientific	Cat# R79007
Experimental models: Organisms/strains
gl-CH31 knock-in mice	Duke University/DHVI & ABS	N/A
Oligonucleotides
P5-H10-leader:TCGTCGGCAGCGTCAGATGTG TATAAGAGACAGCTGTCAGTAACTGTAGGTGTGT	This paper	N/A
P7-IgM:GTCTCGTGGGCTCGGAGATGTGTATAA GAGACAGCGAGGGGGAAGACATTTGGG	This paper	N/A
P7-IgG1: GTCTCGTGGGCTCGGAGATGTGTATA AGAGACAGAGACAGATGGGGGTGTCGTT	This paper	N/A
P7-IgG2b: GTCTCGTGGGCTCGGAGATGTGTAT AAGAGACAGAGACTGATGGGGGTGTTGTT	This paper	N/A
P7-IgG3: GTCTCGTGGGCTCGGAGATGTGTATA AGAGACAGACAGATGGGGCTGTTGTTGT	This paper	N/A
P7-IgA: GTCTCGTGGGCTCGGAGATGTGTATAA GAGACAGTGGTGGGATTTCTCGCAGAC	This paper	N/A
P5-ox-leader: TCGTCGGCAGCGTCAGATGTGTA TAAGAGACAGTGCTAATCAGTGCCTCAGTCATAA	This paper	N/A
P7-mouse Kappa: GTCTCGTGGGCTCGGAGATG TGTATAAGAGACAGTGGATGGTGGGAAGATGGAT	This paper	N/A
Software and algorithms
FlowJo	FlowJo	https://www.bdbiosciences.com/en-us/products/software/flowjo-v10-software
Prism v8	Graphpad	https://www.graphpad.com
Adobe Illustrator 2021	Adobe	https://www.adobe.com
R v.4.1.2	Comprehensive R archive network (CRAN)	https://cran.r-project.org/
RStudio 2022.02.3	RStudio	https://www.rstudio.com/
Other
Superdex 200 Increase 10/300 SEC column	Cytiva	Cat# 28-9909-44
Vivaspin 20, 100.000 MWCO PES	Sartorius	Cat# VS2042
Steritop-GP Filter Unit 0.22μm	Millipore	Cat# SCGPT05RE
ELISA-plate, half-area, 96W	Greiner Bio One	Cat# 675061