Table 2. Direct comparison of the apparent affinities (K_D values, nM) determined by solution methods (MSD and KinExA) and SPR (Biacore 8K) on flat chips (average of C1 and CMD-P) and 3D-hydrogels (average of CM5 and CMD200M).

Thirty-two mAbs are included for this comparison and are ranked by their MSD/SPR affinity correlation (best to worst). ND = not determined; NB = non-binder in the assay; Bold = k_d-limited in the Biacore SPR capture-based assay. See Fig 4B.

mAbID	Analog of indicated INN	MSD KD (nM)	KinExA KD (nM)	Biacore KD (nM) flat	Biacore KD (nM) 3D-hydrogel	KD (flat)/ MSD ratio	KD (3D-hydrogel) /MSD ratio
mAb29		0.84	ND	2.0	3.5	2	4
mAb12		1.60	1.69	6.3	11	4	7
mAb21	sintilimab	0.028	ND	<0.12	<0.21	4	7
mAb34		0.11	0.059	<0.46	<0.85	4	8
mAb31		0.14	ND	0.60	1.2	4	8
mAb13	pembrolizumab	0.59	ND	2.5	5.3	4	9
mAb15	balstilimab	2.00	2.13	8.7	14	4	7
mAb33		0.92	1.2	4.2	8.8	5	10
mAb01		0.30	ND	1.5	2.8	5	9
mAb16	dostarlimab	0.18	0.2	0.87	1.7	5	9
mAb05		0.42	0.55	2.1	3.4	5	8
mAb17	camrelizumab	0.47	ND	2.4	4.5	5	10
mAb03	tislelizumab	0.024	0.038	0.13	0.26	5	11
mAb20		0.017	ND	<0.10	<0.20	6	12
mAb22	nivolumab	0.60	ND	3.5	7.4	6	12
mAb06		0.032	ND	0.19	0.37	6	12
mAb04	retifanlimab	0.056	ND	0.35	0.65	6	12
mAb23	cemiplimab	0.13	0.22	0.82	1.9	6	14
mAb19	sasanlimab	0.020	ND	<0.13	<0.30	7	15
mAb27		0.45	0.35	3.0	6.7	7	15
mAb30		0.11	0.077	0.77	1.5	7	14
mAb10		0.48	ND	3.4	6.7	7	14
mAb08		1.00	ND	8.0	12	8	12
mAb09		0.092	0.14	<1.4	<5.5	15	60
mAb28		0.0064	ND	<0.13	<0.30	21	46
mAb32		0.12	0.225	2.6	5.0	22	42
mAb18		0.0035	0.0035	<0.17	<0.34	48	97
mAb26		0.036	ND	2.8	5.1	79	140
mAb07		NB	ND	33	37	ND	ND
mAb24		NB	5.2	15	23	ND	ND