Standard curve of IFN-alpha matched pair antibodies: Sandwich ELISA analysis of IFN-alpha matched pair antibodies Elisa assay was performed by coating wells of a 96-well plate with 50 µl per well of capture antibody HA721290 [PS00-80] diluted in carbonate/bicarbonate buffer, at a concentration of 4 µg/mL overnight at 4℃. Wells of the plate were washed, blocked with 150 µl 1% BSA/PBST blocking buffer, and incubated with serial diluted recombinant IFN-alpha protein starting from 20 ug/ml to 19 pg/ml for 1 hour at 37℃. The plate was washed and incubated with 50 µl per well of detect antibody [PS00-79] (Biotin, 1:2,000) for 1 hour at 37℃. Then the plate was washed and incubated with 50 µl per well of Streptavidin-HRP for 0.5 hour at 37℃. Detection was performed using an Ultra TMB Substrate for 10 minutes at room temperature in the dark. The reaction was stopped with sulfuric acid and absorbances were read on a spectrophotometer at 450 nm.