TABLE 2.
Loss of B. burgdorferi pathogenicity with in vitro passage in immunocompetent micea
| Mouse | Isolate | Day of sacrifice | Infection (no. of specimens positive/no. examined)
|
Arthritis (no. of mice with arthritis/no. examined) | Carditis (no. of mice with carditis/no. examined) | ||
|---|---|---|---|---|---|---|---|
| Blood | Inoculation site | Bladder | |||||
| C3H | cN40 | 21 | 1/5 | 4/5 | 5/5 | 5/5 | 5/5 |
| p22 | 21 | 2/5 | 2/5 | 5/5 | 3/5 | 3/5 | |
| p51 | 21 | 0/5 | 2/3 | 4/5 | 0/5 | 1/5 | |
| N40-75 | 21 | 1/5 | 4/5 | 3/5 | 0/5 | 0/5 | |
| N40-75 | 60 | 0/5 | 4/5 | 4/4 | 0/5 | 0/5 | |
| N40-75 (107) | 21 | 0/5 | 3/4 | 2/3 | 0/5 | 0/5 | |
| B6 | cN40 | 21 | 0/5 | 5/5 | 5/5 | 0/5 | 5/5 |
| N40-75 | 21 | 0/5 | 3/5 | 4/5 | 0/5 | 0/5 | |
a
C3H and B6 mice were infected with cN40 or its derivatives (p22, p51, and N40-75) obtained by in vitro culturing. Mice were infected with 104 spirochetes, unless otherwise indicated, and necropsied at 21 or 60 days after infection. Arthritis and carditis were assessed in a blinded fashion.