REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
CD19 BV786 (Clone SJ25C1)	Beckton Dickinson	Cat#563325; RRID:AB_2744314
CD24 BV711 (Clone ML5)	Beckton Dickinson	Cat#56340; RRID: AB_2631261
CD27 BV510 (Clone M-T271)	Beckton Dickinson	Cat#740167; RRID: AB_2739920
CD38 BV421 (Clone HIT2)	Beckton Dickinson	Cat#562444; RRID: AB_11151894
IgG BV650 (Clone G18-145)	Beckton Dickinson	Cat#740596; RRID: AB_2740297
IgM APC (Polyclonal)	Jackson ImmunoResearch	Cat#709-136-073; RRID: AB_2340524
Streptavidin PE	Beckton Dickinson	Cat#554061; RRID: AB_10053328
Streptavidin BUV395	Beckton Dickinson	Cat#564176; RRID AB_2869553
Streptavidin FITC	Beckton Dickinson	Cat#554060; RRID: AB_10053373
Streptavidin PE-Cy7	Beckton Dickinson	Cat#557598; RRID: AB_10049577
Biological samples
Human peripheral blood	This study, Bambino Gesù Children Hospital, Rome, Italy	N/A
Human saliva	This study, Bambino Gesù Children Hospital, Rome, Italy	N/A
Chemicals, peptides, and recombinant proteins
Biotinylated Recombinant SARS-CoV-2 Spike His-tag	R&D Systems	Cat#BT10549-050
Biotinylated Receptor Binding Domain	This study, Takis, Rome, Italy	N/A
Critical commercial assays
Elecsys® Anti-SARS-CoV-2	Roche Diagnostics	Cat#09 203 079 190
Elecsys® Anti-SARS-CoV-2 S	Roche Diagnostics	Cat#09 289 275 190
LIAISON® SARS-CoV-2 TrimericS IgG assay	Diasorin	Cat#311510D
ELISA Anti-SARS-CoV-2 IgA	Euroimmun	Cat#EI 2606-9601 A
SARS-CoV-2 isolate SARS-CoV2/Human/ITA/PAVIA10734/2020, clade G, D614G (S)	INMI	Cat#008V-04005
EZ-LinkTM Sulfo-NHS-LC-Biotin reaction kit	ThermoScientific	Cat#21335
QIAamp Viral RNA Mini Kit	QIAGEN	Cat# 52904
Software and algorithms
FlowJo 10	FLOWJO, LLC	https://www.flowjo.com
Prism 8	GraphPad software	https://www.graphpad.com/scientific-software/prism/
RStudio	R Foundation for statistical computing	https://www.rstudio.com/
Other
PANGOLIN v3.1.15	Github	https://github.com/hCoV-2019/pangolin
Simple linear regression model code	This study	https://data.mendeley.com/datasets/3yxkps6msr/1