Table 2.

Definition of the antigenic index

Dilution level of test serumOD of ELISA well coated with:
GST-EBO- or GST-MBG-GST
NP/C-halfNP5NP6NP7NP8
500>1.9991.130>1.9990.893>1.9990.324a
1,000>1.9990.4150.9150.775>1.9990.223
2,000>1.9990.4820.6240.826>1.9990.25
4,000>1.9990.4070.3790.3301.8140.236
8,0001.3860.2550.4950.2041.2840.222
16,0000.9260.2430.4030.2530.7630.184
32,0000.4580.1460.2070.2650.4700.271
64,0000.4420.220.1380.3150.2940.267
Calculationb >64,000/5004,000/50016,000/5004,000/50032,000/500500/500
Antigenic index>1288328641
  • a The threshold was defined as the OD of the GST-coated well at a 1:500 dilution, 0.324 in this case. For each antigen, the OD at the maximum dilution level at which the OD is higher than the threshold is underlined.

  • b The antigenic index of each GST-EBO-NP and GST-MBG-NP fragment was calculated as the maximum dilution level at which the OD was over the threshold divided by the dilution level at the threshold.