Fig 5.
Protection against mycobacterial infection initiated by pP24-Mtb immunization. Four weeks following the last immunization, mice were intranasally challenged with 1 × 107 CFU of M. bovis BCG. (A and B) Four weeks postchallenge, the bacterial loads in the lungs (A) and spleens (B) were measured. The data are presented as the means plus SD (n = 6) and are from one representative experiment of three separate experiments. Values that are statistically significantly different (P < 0.05) are indicated by a short horizontal line and an asterisk. (C) Paraffin sections from lung tissues were stained with hematoxylin and eosin (HE) and evaluated for the level of lung inflammation. (D) Representative histology sections depict lung tissue of immunized mice, with a lung section of a healthy (normal) mouse as a negative control. Individual experiments were conducted three times, with the results from one representative experiment shown. Magnification, ×200.