Mouse-specific serum IgG subclass responses to JEV DNA immunization were determined by ELISA.

Sera (1∶200) were collected from vaccinated mice (n = 10) three weeks post-immunization. Values reported above for each group are the mean ± SD of the OD at 492 nm. The solid bars represent the IgG1 subtype, and the hollow bars represent the IgG2a subtype. The IgG2a/IgG1 ratios of three groups are 0.613±0.045, 0.734±0.057 and 0.954±0.062, respectively.