TABLE 2.
Effects of BCG immunization on PFU titers of challenge virusesa
| Challenge virus and mouse strain | Immunization (n) | Time of virus challenge (wks after BCG or sham immunization) | Day postchallenge that titers were determined | Titer (log10 PFU/ml) inb:
|
||
|---|---|---|---|---|---|---|
| Spleen | Liver | Fat pads | ||||
| VV | ||||||
| C57BL/6 | BCG (3) | 11 | 1 | 2.5 ± 0.31 | 3.1 ± 0.43 | 3.5 ± 0.28 |
| Sham (3) | 4.0 ± 0.23** | 4.3 ± 0.26* | 4.5 ± 0.16** | |||
| C57BL/6 | BCG (3) | 10 | 3 | 1.3 ± 0.45 | <2.0 ± 0.00 | 3.0 ± 1.6 |
| Sham (3) | 2.8 ± 0.78* | 2.8 ± 0.43* | 5.7 ± 0.29* | |||
| C57BL/6 | BCG (5) | 28 | 3 | 1.5 ± 0.55 | 2.3 ± 0.30 | 4.2 ± 0.85 |
| Sham (5) | 3.1 ± 0.25** | 3.9 ± 0.59** | 5.4 ± 0.42* | |||
| B10 | BCG (4) | 13 | 2 | <1.0 ± 0.00 | <2.0 ± 0.00 | 2.3 ± 1.2 |
| Sham (4) | 4.1 ± 0.10** | 4.4 ± 0.20** | 4.4 ± 0.32* | |||
| B10.D2 | BCG (4) | 13 | 2 | <1.0 ± 0.00 | <2.0 ± 0.00 | 3.3 ± 1.3 |
| Sham (4) | <1.0 ± 0.00 | 3.3 ± 0.25** | 4.4 ± 0.28 | |||
| LCMV clone 13 | ||||||
| C57BL/6 | BCG (3) | 12 | 3 | 5.3 ± 0.65 | 4.3 ± 0.30 | |
| Sham (3) | 5.3 ± 0.63 | 4.0 ± 0.30 | ||||
| C57BL/6 | BCG (3) | 17 | 3 | 5.5 ± 0.20 | 5.0 ± 0.28 | |
| Sham (3) | 5.4 ± 0.44 | 5.1 ± 0.22 | ||||
a
Mice of the designated strains were immunized with BCG or sham immunized, and at the designated time postimmunization they were challenged with either VV or LCMV, as described in Materials and Methods.
b
On the designated day postchallenge, mice were sacrificed and viral titers were assessed in tissue homogenates by plaque assay on Vero cells. Spleen and liver titers (both challenge groups) and fat pad titers (only the VV challenge group) are expressed as the log10 PFU/ml. Statistically significant differences between BCG- and sham-immunized mice: *, P < 0.05; **, P < 0.01 (Student's t test).