Percentage of survival in heat-killed vaccinated BALB/c mice. BALB/c mice were vaccinated with 1 × 105 CFU/100 μl of HK B. mallei by intraperitoneal injection. Two weeks post HK vaccination, mice were injected i.p. with 2 × 107 CFU/100 μl of live B. mallei (~20 LD50). HK vaccination resulted in a 40% survival rate for HK-vaccinated mice with a mean survival time (MST) of 8 days (p = 0.1526). Immunologically naïve mice demonstrated 100% mortality by day 6. Data are representative of 2 independent experiments.