ELISA (96-well) plates were coated with 0.5 µg/mL of the therapeutic antibody or with non-related human IgG protein (~0.5 µg/mL) overnight at 4ºC. Plates were washed 3 times with PBS containing 0.05% Tween (PBST). Hybridoma supernatant or serially diluted serum was added to the plate (50 µL/well) and incubated at room temperature for 1 hour. After 3X wash with PBST goat anti-mouse-HRP (Cat#1030-05, Southern Biotech, Birmingham, AL), was added to the plates (1:2000; 50 µL/well) and incubated at room temperature for 30 minutes. After 3X wash with PBST, 50 µL/well of 1-Step Ultra TMB ELISA Substrate Solution (Cat# 34029, ThermoFisher Scientific, Waltham, MA) was added to plates and incubated at room temperature for 5 minutes followed by the addition of 50 µL/well TMB Stop Solution (Cat# 50-85-06, SeraCare, Milford, MA). The colorimetric signal at 450nm was measured using a SpectraMax 384 plate reader (Molecular Devices, San Jose, CA).