Table 1.

Biophysical properties of anti-TcdA V_HH constructs.

Antibody	Linker	Mr (Da)	Yield (mg/L)	Mon. (%)c	EC50 (pM)d	kd (s−1)e	Dissociation (%)f	T1/2 (h)g
A20	na	15,670	19a	100	194 ± 13	(7.5 ± 0.1) × 10−3	88.4 ± 0.3	0.03
A26	na	16,016	15a	100	14,620 ± 2,320	(2.5 ± 0.1) × 10−2	98.9 ± 0.2	0.01
A20-A20	[GS]6	28,679	80b	100	42 ± 3	(1.8 ± 0.2) × 10−5	7.7 ± 1.1	10.6
A26-A26	[GS]6	29,371	110b	100	32 ± 3	(3.6 ± 0.4) × 10−5	13.5 ± 0.7	5.4
A20-A26	[GS]6	29,025	114b	100	34 ± 2	(6.9 ± 1.5) × 10−6	3.9 ± 0.5	28.1
A26-A20	[GS]6	29,025	112b	100	47 ± 2	(1.7 ± 0.2) × 10−5	7.5 ± 1.1	11.3
CDA1 IgG	na	145,580	80	nd	nd	(2.2 ± 0.2) × 10−5	18.0 ± 0.6	8.8

na, not applicable; nd, not determined. ^aProtein purification yield from 1 L E. coli cultures. ^bProtein purification yield extrapolated from 100 mL HEK293-6E cultures. ^cPercent monomer peak area determined from size exclusion chromatograms. ^dDetermined by ELISA. ^eDetermined by SPR at 37°C with a 5 min (monomers) or 60 min (dimers, mAb) dissociation. Values are mean ± SD from three technical replicates. ^fPercent dissociation of SPR response after 5 min (monomers) or 60 min (dimers, mAb). Values are mean ± SD from three technical replicates. ^gSPR-calculated half-life (T_1/2 = 0.693/k_d).