TABLE 1.
Serum-mediated bacterial elimination in SCID micea
| Treatment | Admin. day | Analysis day p.i. | Infectivity index for expt:
|
||
|---|---|---|---|---|---|
| 1 | 2 | 3 | |||
| Buffer | 0 | 3 | 2 | 2 | 3 |
| 0 | 10 | 3 | 5 | 5 | |
| 0 | 17 | 5 | 5 | 0 | |
| 0 | 24 | 6 | 5 | 5 | |
| Normal serum | 0 | 3 | 2 | 1 | 3 |
| 0 | 10 | 5 | 0 | 0 | |
| 0 | 17 | 5 | 3 | 4 | |
| 0 | 24 | 6 | 3 | nd | |
| Immune serum | 0 | 3 | 0 | 0 | 0 |
| 0 | 10 | 0 | 0 | 0 | |
| 0 | 17 | 1 | 1 | 0 | |
| 0 | 24 | 6 | 2 | 6 | |
| Immune serum | 3 | 3 | nd | nd | nd |
| 3 | 10 | 0 | nd | 0 | |
| 3 | 17 | 1 | nd | 0 | |
| 3 | 24 | 5 | nd | 5 | |
Data were derived from semiquantitative PCR analyses of E. chaffeensis 16S rDNA, as described previously (38). The infectivity index was determined by analysis of the PCR products, which were assigned a score from 1 to 6 on the basis of a visual estimation of band intensities. Samples from different experiments were normalized to standardized quantities of E. chaffeensis DNA obtained from cell culture. The semiquantitative analyses in general underestimated high bacterial loads. P values were determined by combining the control and serum-treated groups from each analysis day and were as follows: 0.012 (day 3), 0.002 (day 10), 0.004 (day 17), 0.5, (day 24). For details, see Materials and Methods. nd, not determined; p.i., postinfection; admin., administration.