Table 1

Neutralizing antibody titer against: ^b

Dose of DENV2

antigen (PFU)^a

DENV1

DENV2

DENV3

DENV4

5.0 x 10⁷

1:160

1:320

1:160

5.0 x 10⁶

1:160

1:80

5.0 x 10⁵

1:80

1:20

PBS

1:40

1:20

1:40

1:20

^aGroups of six 4-week-old male ddY mice were preimmunized with the indicated doses of DENV2 antigen or inoculated with PBS as a control
^bFour weeks after the preimmunization, mice were vaccinated with 40 µg of the dengue tetravalent DNA vaccine (10 µg for each type) twice, with a 3-week interval. Two weeks after the second dose of the DNA vaccine, mice were bled and pooled sera were examined for neutralizing antibodies

Table 1: Neutralizing antibody titers in dengue tetravalent DNA vaccine-vaccinated mice with or without preimmunization with DENV2.