Table 1.
Anti-OPV memory CD8+ T cells protect mice from mousepox and death after footpad ECTV challenge
| Experiment | Recipient inoculation | Donor immunization | Donor boost | Time boost to transfer | Time transfer or immunization to challenge | Mousepox/total | Dead/total |
|---|---|---|---|---|---|---|---|
| 1 | Memory CD8+ T cells | VACV | ECTV | 1 month | 1 day | 0/5 | 0/5 |
| Naïve CD8+ T cells | — | — | — | 1 day | 5/5 | 3/5 | |
| Antiserum | VACV | ECTV | >2 months | 1 day | 0/5 | 0/5 | |
| VACV | NA | NA | NA | 1 month | 0/5 | 0/5 | |
| 2 | Memory CD8+ T cells | VACV | ECTV | 4 months | 1 day | 0/5 | 0/5 |
| Naïve CD8+ T cells | — | — | — | 1 day | 5/5 | 3/5 | |
| 3 | Memory CD8+ T cells | VACV | VACV | >2 months | 1 day | 0/5 | 0/5 |
| Naïve CD8+ T cells | — | — | — | 1 day | 5/5 | 5/5 | |
| 4 | Memory CD8+ T cells | VACV | VACV | 1 year | 1 day | 0/5 | 0/5 |
| — | NA | NA | NA | NA | 5/5 | 5/5 | |
| 5 | Memory CD8+ T cells | VACV | VACV | >2 months | 1 day | 0/5 | 0/5 |
| Memory CD8− cells | VACV | VACV | >2 months | 1 day | 5/5 | 5/5 | |
| 6 | Memory CD8+ T cells | VACV | VACV | >2 months | 1 month | 0/5 | 0/5 |
| Naïve CD8+ T cells | — | — | — | 1 month | 5/5 | 5/5 | |
| 7 | Memory CD8+ T cells | VACV | VACV | >2 months | 4 months | 0/5 | 0/5 |
| Naïve CD8+ T cells | — | — | — | 4 months | 5/5 | 5/5 |
Naïve BALB/c mice were inoculated with purified CD8+ (≈5 × 106 per mouse) or CD8− (≈107 per mouse) LN and spleen cells from donor mice that had been infected and boosted (1 month apart) with the indicated viruses. One day, 1 month, or 4 months later, recipient mice were challenged with ECTV in the footpad, and mousepox (assessed by clinical signs) and death were determined. All experiments are representative of at least three repeats except for experiment 6, which was performed once. In experiments 5 and 6, anti-VACV antibody was assayed in sera just before challenge. No anti-VACV antibody was detected at dilutions of the sera ranging from 10−1 to 10−8. The time of death for all nonsurviving mice was 9 ± 2 days. NA, not applicable.