Attenuated virulence of the B. mallei bopA mutant. BALB/c mice (n=8) were challenged by i.n. delivery with B. mallei or the bopA mutant (GCW005) and monitored for survival. (a) GCW005 animals challenged with 2 LD50 resulted in a 50 % survival rate (P=0.022) compared with that of the wild-type. Control animals were dosed with vehicle only. , Control; ▴, B. mallei 2 LD50; ▵, GCW005 2 LD50; ○, GCW005 4 LD50. (b) At day 10 p.i., lungs and spleen were harvested from surviving animals infected with wild-type (filled columns, n=1) or GCW005 (shaded columns, n=4) and plated for bacterial burden. No organisms were detected in GCW005-infected lungs. Data are expressed as means±sem for GCW005.