TABLE 1.
Sensitization with environmental mycobacteria blocks the protective effect of BCG
| Group of micea | Result inb:
|
||||
|---|---|---|---|---|---|
| Spleen
|
Lung
|
||||
| CFUc | Log10 resistanced | CFU | Log10 resistance | ||
| Naive | 4.44 ± 0.13 | 6.34 ± 0.11 | |||
| BCG | 3.76 ± 0.16 | 0.68* | 5.21 ± 0.08 | 1.13* | |
| Sensitization | 4.36 ± 0.17 | 0.08 | 6.14 ± 0.11 | 0.20 | |
| Sensitization + BCG | 4.33 ± 0.17 | 0.11 | 6.25 ± 0.06 | 0.09 | |
a
Naive or sensitized mice were BCG vaccinated (5 × 104 CFU) followed by aerosol challenge with virulent M. tuberculosis.
b
The experiment was repeated twice with similar results.
c
Bacterial numbers determined by growth of individual whole-organ homogenates 6 weeks postinfection.
d
Protective effect expressed as the log10 reduction in bacterial loads compared to those of naive mice. Bacterial numbers significantly different (P < 0.05) from those seen in naive mice are indicated by an asterisk.