Animals were provided rodent

diet and tap water ad libitum throughout the study. Research was conducted at the United States Army Medical Research Institute of Infectious Diseases (USAMRIID) and was in compliance with the Animal Welfare Act and other federal statutes and regulations relating to animals and experiments involving animals. USAMRIID is fully accredited by the Association for Assessment and Accreditation of Laboratory Animal Care International. this website Mice were vaccinated SC or IM with fV3526 alone or formulated with adjuvant on Day 0 and 28. Due to restrictions in the volume of inoculum that can be delivered to a mouse via the IM route, the SC vaccinated mice received five times more viral protein (0.2 μg) per dose than IM vaccinated mice

(0.04 μg) (Table 1). For SC vaccination, 0.5 mL of inoculum was administered to the interscapular area. For IM vaccinations, 0.025 mL was administered into the muscle of each hind limb. C84 was administered according to the dosage (4 μg), route (SC), and schedule (0, 7, and 28) used in previously published animals studies [13] and [28] and as administered to human vaccinees [8] and [29] to allow comparisons between the data collected in this study to historical studies. Further, the dosage, route, schedule and use of adjuvants with C84 was not evaluated as the intent of the comparisons to be made with C84 were to show fV3526 formulations are as good as or better than C84 in its current formulation as the US government does not intend to fund further development of C84 as a VEEV vaccine. Sham-vaccinated mice received PCM either SC or IM and adjuvant control mice received Viprovex®, Alhydrogel™, SRT1720 cell line CpG or CpG + Alhydrogel™ at the same concentrations and on the same schedule as administered in experimental groups with fV3526. On Day 21 and 49 post-primary vaccination, blood was collected

from all mice for measurement of antibody responses. Mice were challenged on Day 56 with 1 × 104 pfu VEEV TrD by the aerosol or SC route. Aerosol exposures were conducted by putting mice in wire cages into a chamber where they were exposed to aerosolized virus for 10 min. Virus collected aminophylline in an all-glass impinger was titrated to determine the concentration of virus (pfu/L) in air using a previously described plaque assay method [30] and the volume inhaled was estimated using Guyton’s formula [31]. Mice were monitored daily for signs of illness for 28 days post-challenge at which time surviving mice were euthanized. One iteration of each vaccination-challenge study was conducted, unless otherwise noted. Virus-neutralizing antibodies in the immunized and control mice were determined as previously described [32] using live VEEV TrD virus as target antigen. Sera were serially diluted two-fold with virus and incubated overnight at 4 °C. The serum-virus mixtures were added to Vero cell monolayers for 1 h at 37 °C, after which the cells were overlaid with 0.