WNV-specific ELISA antibody titers in mice immunized with recombinant baculoviruses. Mice were intramuscularly vaccinated with recombinant baculovirus Bac-G-prM/E or Bac-prM/E, or control virus, while E-DIII protein vaccine used as a positive control (for details, see materials and methods, mouse immunization). Serum samples were collected at 3 and 6 weeks after the fist immunization. Presence of antibodies was analyzed by ELISA at a 1:500 serum dilution. The data are expressed as average titers per group (n = 6) ± SD.