Figure 4

ELISA with sera from mice that survived aerosol challenge with various doses of B. pseudomallei 1026b and B. mallei ATCC 23344. Serum samples were serially diluted and placed in duplicate wells of plates coated with purified His-tagged protein encompassing aa 392–1068 of B. pseudomallei 1026b BpaC. Goat α-mouse Abs conjugated to HRP were used as secondary Abs. The y-axis shows absorbance at a wavelength of 650 nm, which is indicative of antibody binding to antigens coating the plates. The x-axis represents two-fold dilutions of sera starting at 1:100 to 1:12,800. The results are expressed as the mean absorbance (±standard deviation). Closed circles show sera from mice inoculated with 10⁴ B. pseudomallei bacteria (panel A). Open circles show sera from mice infected with 10³ organisms (panels A and B). Open triangles show sera from mice inoculated with 10² bacteria (panels A and B). Closed diamonds show sera from mice infected with 10¹ CFU of B. mallei ATCC 23344 (panel B). Blue squares represent sera from control mice that were inoculated with 50 μL of PBS using the Microsprayer (panels A and B). Of note, sera from mice that survived acute infection by B. pseudomallei and B. mallei are described elsewhere[67].