FIG. 6.

Clearance of M. bovis BCG-P and M. tuberculosis H37Rv ΔleuD (mc²3032) in the tissues of immunocompetent BALB/cJ mice. The mice were immunized via the lateral tail vein with 5 × 10⁶ CFU of M. bovis BCG-P (solid symbols) or a similar number of mc²3032 ΔleuD cells (open symbols). At the indicated times after immunization, the mice were sacrificed and their organs were collected and homogenized. The bacterial burdens in the lungs (triangles), spleen (squares), and liver (circles) were determined by serial dilution and plating of the organ homogenates onto leucine-supplemented medium. The error bars represent the standard deviations for the means of four to five mice per experimental group.