Figure 2

Schematic drawing of the pulmonary delivery system used for aerosolized pDNA administration in conscious sheep via inhalation. Room air was drawn through a bacterial/viral filter and a one-way valve placed in the inspiratory limb. Nebulized plasmid DNA was introduced into the inspiratory arm of the system via the 30 MHz SAW device positioned in a chamber in line with a mechanical ventilator to facilitate controlled respiration in sheep. The closed respiratory circuit was completed with the placement of an endotracheal tube via the nasal passage. Each sheep received three immunizations, once (20-30 minute aerosolization) per three-week period, with a pDNA aerosol containing sterile pVR1020 encoding HA (85 μg/ml) in 5% dextrose.