Figure 2. Persistence of infection.

BALB/c mice were infected with 10⁷ bioluminescent Brucella melitensis GR023. A) Colony forming units were determined by culturing serial dilutions of lysed splenocytes for 3–5 days at 37°C. B) Images were captured with a ten minute exposure on an IVIS Imaging System. The rainbow scale of luminescence for each image is in approximate photons. Age-matched control mice are shown in the rightmost position of each individual photo. The day post infection when the images were collected is noted in the bottom right corner of each frame.