TABLE 1.
Protection of mice immunized with E. rhusiopathiae strains against lethal challenge with a homologous virulent straina
| Immunization | Immunizing dose (CFU) | No. of survivors/total |
|---|---|---|
| YS-1 | 108 | 4/4b |
| 106 | 4/4b | |
| 104 | 3/4 | |
| YS-19 | 108 | 4/4b |
| 106 | 4/4b | |
| 104 | 4/4b | |
| YS-24 | 108 | 4/4b |
| 106 | 4/4b | |
| 104 | 3/4 | |
| Control | 0/4 |
a
Groups of four BALB/c mice were immunized subcutaneously with 0.1-ml volumes of appropriate dilutions of the bacterial suspensions. After immunization, mice were challenged subcutaneously with approximately 100 50% lethal doses of the Fujisawa-SmR strain and observed for clinical symptoms and death for 14 days.
b
Significant difference (P < 0.05) compared to the control determined by Fisher’s exact test.