FIG. 4.

Comparison of the CDC assay to two previously developed methods for measuring JEV NS1 antibodies in horse sera. Percentages of specific cell lysis shown by the one-dilution method (upper graphs) and NS1 antibody titers shown by the endpoint method (lower graphs) obtained in the present study using the CDC assay were compared to NS1 antibody levels shown by ELISA (left graphs) or NS1 antibody titers shown by the immunostaining method (right graphs), which were obtained in our earlier studies (12, 13). Dotted lines indicate cutoff values for differentiating positive from negative samples. NS1 antibody levels/titers of 4.32% (the one-dilution method), 1:10 (the endpoint method), 0.122 (ELISA), and 1:80 (the immunostaining method) or higher were determined to be positive.