REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
Goat anti-human IgG, 1:4000	Jackson	109-035-098; RRID: AB_2337586
Goat anti-human IgA, 1:750	Thermo Fisher Scientific	31417; RRID: AB_228253
Goat anti-human IgM, 1:3,000	Sigma-Aldrich	A6907; RRID: AB_258318
Mouse anti-human IgG1, 1:3,000	SouthernBiotech	9054–05; RRID: AB_2796627
Mouse anti-human IgG2, 1:3,000	SouthernBiotech	9060–05; RRID: AB_2796633
Mouse anti-human IgG3, 1:3,000	SouthernBiotech	9210–05; RRID: AB_2796699
Mouse anti-human IgG4, 1:3,000	SouthernBiotech	9200–05; RRID: AB_2796691
Mouse anti-human IgG4, 1:500	Invitrogen	A-10654; RRID: AB_2534054
Chemicals, Peptides, and Recombinant Proteins
spike ECD (for ELISA), HEK293, 1 μg/mL	(Emmenegger et al., 2020), Oxford	N/A
WT spike S1 (for ELISA), HEK293, 1 μg/mL	AcroBiosystems	S1N-C52H2
WT spike S2 (for ELISA), HEK293, 1 μg/mL	AcroBiosystems	S2N-C52H5
WT RBD (for ELISA), HEK293, 1 μg/mL	(Emmenegger et al., 2020), Oxford	N/A
WT RBD (for MAAP), HEK293, 1 μg/mL	Sino Biological	40592-V08H
Delta RBD (for ELISA, MAAP), HEK293, 1 μg/mL	Sino Biological	40592-V08H90
Omicron RBD (for ELISA, MAAP), HEK293, 1 μg/mL	Sino Biological	40592-V08H121
NC (for ELISA), HEK293, 1 μg/mL	AcroBiosystems	NUN-C5227
Purified IgA (for ELISA), Human serum, 2.5 μg/mL	Sigma-Aldrich	14036
Purified IgM(for ELISA), Human serum, 2.5 μg/mL	Sigma-Aldrich	18260
Recombinant human IgG1 (for ELISA), HEK293, 2.5 μg/mL	Mabylon AG	N/A
Recombinant human IgG2 (for ELISA), Human myeloma, 2.5 μg/mL	EMD Millipore	AG504; RRID: AB_97839
Recombinant human IgG3 (for ELISA), Human myeloma, 2.5 μg/mL	EMD Millipore	AG506; RRID: AB_97840
Recombinant human IgG4 (for ELISA), HEK293, 2.5 μg/mL	Mabylon AG	N/A