Fig. 2

Optimization of test parameters for the cELISA immunoassay. a The coating antigen concentrations of 2, 4, 6 and 8 μg/mL and 2-fold serial dilutions of the 2F8 purified ascites varied from 0.3125 to 1.25 μg/mL were tested respectively by checkerboard titration. b After the optimal antigen and competitive antibody concentrations were determined, the optimal dilution ratio for test sera was determined by 2-fold serial dilution from 1:5 to 1:80. The combination that gave the highest PI values was determined to be 4 μg/mL antigen, 0.625 μg/mL mAb and 1:5 dilution ratio of test serum. The red vertical dotted lines indicate the optimal working condition