Table 4.
OspC-deficient B. burgdorferi with increased OspA expression registers a slight ID50 increase in SCID mice.a
| Expt, clone, and dose (no. of organisms) | No. of biopsies positive/Total ear biopsies conducted at post-inoculation weeks |
No. of cultures positive/Total specimens examined |
No. of mice infected/Total mice inoculated | ID50 (no. of organisms) | |||||
|---|---|---|---|---|---|---|---|---|---|
| 2 | 3 | 4 | Heart | Joint | Skin | All site | |||
| I | |||||||||
| ΔospC/FL/1 | 18 | ||||||||
| 104 | 3/3 | NDb | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 103 | 3/3 | ND | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 102 | 3/3 | ND | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 101 | 1/3 | ND | ND | 1/3 | 1/3 | 1/3 | 3/9 | 1/3 | |
| ΔospC/FL/2 | 18 | ||||||||
| 104 | 3/3 | ND | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 103 | 3/3 | ND | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 102 | 3/3 | ND | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 101 | 1/3 | ND | ND | 1/3 | 1/3 | 1/3 | 3/9 | 1/3 | |
| ΔospC/CpospA/1 | 32 | ||||||||
| 104 | 0/3 | 3/3 | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 103 | 0/3 | 3/3 | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 102 | 0/3 | 0/3 | 3/3 | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 101 | 0/3 | 0/3 | 0/3 | 0/3 | 0/3 | 0/3 | 0/9 | 0/3 | |
| ΔospC/CpospA/2 | 32 | ||||||||
| 104 | 0/3 | 3/3 | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 103 | 0/3 | 3/3 | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 102 | 0/3 | 0/3 | 3/3 | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 101 | 0/3 | 0/3 | 0/3 | 0/3 | 0/3 | 0/3 | 0/9 | 0/3 | |
| II | |||||||||
| ΔospC/FL/1 | 18 | ||||||||
| 103 | 3/3 | ND | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 102 | 3/3 | ND | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 101 | 1/3 | ND | ND | 1/3 | 1/3 | 1/3 | 1/9 | 1/3 | |
| ΔospC/FL/2 | 18 | ||||||||
| 103 | 3/3 | ND | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 102 | 3/3 | ND | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 101 | 1/3 | ND | ND | 1/3 | 1/3 | 1/3 | 3/9 | 1/3 | |
| ΔospC/CpospA/1 | 32 | ||||||||
| 103 | 0/3 | 3/3 | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 102 | 0/3 | 0/3 | 3/3 | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 101 | 0/3 | 0/3 | 0/3 | 0/3 | 0/3 | 0/3 | 0/9 | 0/3 | |
| ΔospC/CpospA/2 | 18 | ||||||||
| 103 | 0/3 | 3/3 | ND | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 102 | 0/3 | 0/3 | 3/3 | 3/3 | 3/3 | 3/3 | 9/9 | 3/3 | |
| 101 | 0/3 | 0/3 | 0/3 | 1/3 | 1/3 | 1/3 | 1/9 | 1/3 | |
The ΔospC/FL/1, ΔospC/FL/2, ΔospC/CpospA/1, and ΔospC/CpospA/2 spirochetes were grown to late-log phase (108 cells per ml) and 10-fold serially diluted with BSK-H medium. Groups of three BALB/c SCID mice each received a single intradermal/subcutaneous dose of 100 μl of bacterial suspension; ear biopsies were performed up to four weeks post-inoculation, starting at week 2. Once all three animals of a dose group became positive, biopsies were no longer performed on the group. All animals were sacrificed 1 month post-inoculation; heart, tibiotarsal joint, and skin specimens were harvested for bacterial isolation. The ID50 values were calculated by the method of Reed and Muench (Reed and Muench, 1938), and determined in two separate experiments.
ND, not determined.