TABLE 1.

Equilibrium cell binding assays

Radiolabeled antibodies in the presence of varying concentrations of unlabeled antibodies were incubated with NR6 cells expressing either EGFR or HER2 or with HCA-7 cells that co-express both EGFR and HER2. Affinity determinations are an average of three assays shown with the S.E.

Cell line/antibody	Kd
	nm
NR6 expressing EGFR
WT anti-EGFR	0.56 ± 0.19
Anti-EGFR Fab	2.07 ± 0.24
One-armed LUZ-Y anti-EGFR	1.15 ± 0.07
Tethered LUZ-Y anti-EGFR/HER2	2.64 ± 0.30
NR6 expressing HER2
wt anti-HER2	0.90 ± 0.13
Anti-HER2 Fab	2.76 ± 0.17
one-armed LUZ-Y anti-HER2	1.72 ± 0.11
Tethered LUZ-Y anti-EGFR/HER2	5.11 ± 0.20
HCA-7 co-expressing
Tethered LUZ-Y anti-EGFR/HER2	0.99 ± 0.13
WT anti-EGFR	0.40 ± 0.08
WT anti-HER2	0.19 ± 0.02
One-armed LUZ-Y anti-EGFR	1.56 ± 0.09
One-armed LUZ-Y anti-HER2	2.18 ± 0.04