Table 3.

EC₅₀ values (nM) of Nb-Fc proteins binding to the tested RBDs of SARS-CoV-2 variants detected by ELISA.

SARS-CoV-2 RBD	aRBD-2-Fc	aRBD-7-Fc	aRBD-2-7-Fc
WT	1.146	0.117	0.156
Alpha	1.204	0.141	0.191
Beta	4.490	NB*	0.517
Gamma	1.834	NB	0.135
Delta	1.537	ND#	0.149
Delta plus	1.330	ND	0.116
Kappa	1.000	NB	0.093
Lambda	1.953	NB	0.165
Omicron BA.1	3.238	NB	0.179
Omicron BA.2	4.731	NB	0.250

^*NB No binding.

^#ND Not defined.