Fig. 4.

Efficiency of vaccine delivery using the device. (A) S. enterica serovar Typhimurium vaccine strain pmrG-HM-D (DV-STM-07) was administered to mice using the device and by the intraperitoneal (I.P) route. The control mice were given phosphate-buffered saline (PBS) delivered using the device. Mice were infected with a lethal dose (10⁷ CFU/mouse) of virulent Salmonella orally, 5 days after the immunization. The MLN, spleen, and liver were aseptically dissected to check the Salmonella burden 4 days after the challenge. Values that are statistically significantly different (P < 0.005 by the Mann-Whitney U test) are indicated by the bracket and two asterisks. (B) Mice (6 mice per group) were infected with a lethal dose (10⁸ CFU/mouse) of virulent Salmonella orally 5 days after immunization as described for the previous experiment, and the percent survival of mice over time was determined. The values for the vaccinated mice and the control mice that were treated with PBS were significantly different (P < 0.0001 by the log rank test). (C) A single dose of DV-STM-07 was delivered using the device, orally, and by the intraperitoneal route, and the serum IgG levels were tested against Salmonella-specific lipopolysaccharide (LPS) using ELISA. Control mice were given PBS delivered using the device. Each symbol represents the value for an individual mouse. The mean value (black line) ± standard deviation (error bars) for each group of mice are shown. Values that are significantly different by Student's t test are indicated by the bracket and asterisks as follows: **, P < 0.005; ***, P < 0.0005.