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 1

VEEV-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 VEEV DNA vaccine, or 5 μg each of the VEEV, WEEV, and EEEV DNA vaccines (3-EEV DNA vaccine) delivered by IM EP or on day 0 with 0.5 ml of the live-attenuated VEEV IND vaccine TC-83 (1 × 10⁴ PFU) delivered by subcutaneous injection. Serum samples obtained on days 21 and 42 were assayed for total IgG anti-VEEV antibodies by ELISA and for VEEV-neutralizing antibodies by PRNT. The group mean log₁₀ ELISA (a) and PRNT₈₀ (b) titers along with the standard error of the mean (SEM) are shown. for comparison of titers between groups. Four weeks after the final vaccination, the mice were challenged with 1 × 10⁴ PFU (~10,000 LD₅₀) of VEEV IAB strain Trinidad donkey 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 and survival curve as compared to negative control group.

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