1 murine macrophages, or growth inside these cells (data not shown). The bpaC mutants did not show defects in resistance to the bactericidal activity of normal human serum (data not shown), which is another biological function commonly associated with Oca autotransporters [2, 3, 19, 65, 66]. Virulence www.selleckchem.com/products/3-methyladenine.html of B. mallei and B. pseudomallei mutant strains and BpaC expression

in vivo To determine whether BpaC contributes to virulence, we calculated the median lethal dose (LD50) of B. pseudomallei and B. mallei mutant strains in a mouse model of aerosol infection. The model entails the use of a Microsprayer® to deliver bacteria directly into the murine lungs [67]. The device generates aerosol particles from the tip of a bent, 23-gauge nebulizing tube attached to a high-pressure stainless Go6983 ic50 steel syringe that contains bacteria. BALB/c mice were anesthetized and placed

in a custom-designed acrylic holder inside a Class II Biosafety cabinet. A modified pediatric otoscope equipped with a light source was then used to introduce the nebulizing tube portion of the Microsprayer® into the trachea of animals, and 50-μL of bacterial suspension was aerosolized into the lungs by pushing the plunger of the high-pressure syringe. ABT737 Following infection, mice were observed daily for clinical signs of illness and morbidity. As shown in Table  2, the bpaC mutation did not have an impact on the LD50 values of B. mallei ATCC 23344 or B. pseudomallei DD503. Tissues (i.e. lungs, spleen, liver)

from mice that survived the acute phase of infection did not show differences in bacterial loads (data not shown). Based on these results, we conclude that the bpaC mutation does not affect the virulence of B. mallei ATCC 23344 or B. pseudomallei DD503 via the aerosol route of infection. Table 2 Median lethal dose determination PAK6 of B. mallei and B. pseudomallei WT and mutant strains Organism Strain Inoculating dose (CFU) Group size % death LD50(CFU) B. mallei a ATCC 23344 (WT) 9,100 5 100       5,550 5 100       910 9 78 346     455 5 40       91 9 11   B. mallei a bpaC KO (mutant) 10,400 5 100       5,200 6 83       1,040 9 100 238     520 5 40       104 9 22   PBS (control) a   0 5 0   B. pseudomallei b DD503 (WT) 380,000 5 100       38,000 5 100 1,202     3,800 5 100       380 5 0   B. pseudomallei b bpaC KO (mutant) 350,000 5 100       35,000 5 100 1,107     3,500 5 100       350 5 0   PBS (control) b   0 5 0   a mice were monitored daily for clinical signs of illness/morbidity for 10 days post-inoculation. b mice were monitored daily for clinical signs of illness/morbidity for 6 days post-inoculation. To gain insight into the immune response to BpaC during infection, we tested sera from mice that survived aerosol challenge with B. mallei ATCC 23344 and B.