Research Article

A Multiagent Alphavirus DNA Vaccine Delivered by Intramuscular Electroporation Elicits Robust and Durable Virus-Specific Immune Responses in Mice and Rabbits and Completely Protects Mice against Lethal Venezuelan, Western, and Eastern Equine Encephalitis Virus Aerosol Challenges

Figure 3

WEEV-specific antibody responses and survival of vaccinated mice. Female BALB/c mice ( per group) were vaccinated on days 0 and 21 with 5 μg of empty vector DNA, 5 μg of the WEEV DNA vaccine, or 5 μg each of the VEEV, WEEV, and EEEV DNA vaccines (3-EEV DNA vaccine) delivered by IM EP or 0.5 ml of the formalin-inactivated WEEV IND vaccine delivered by subcutaneous injection. Serum samples obtained on days 21 and 42 were assayed for total IgG anti-WEEV antibodies by ELISA and for WEEV-neutralizing antibodies by PRNT. The group mean log10 ELISA (a) and PRNT80 (b) titers along with the SEM are shown. for comparison of titers between groups. Four weeks after the final vaccination, the mice were challenged with 2 × 104 PFU (~500 LD50) of WEEV strain CBA87 by the aerosol route. Kaplan-Meier survival curves indicating the percentage of surviving mice at each day of the 28-day postchallenge observation period are shown (c). for survival rate as compared to negative control group.
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