Absence of CTLA-4 in vivo leads to CD8+T-cell-mediated C1498/B7-1 regression at tumor cell numbers that normally lead to tumor progression
| Tumor hosts4-150 . | Tumor injected4-151 . | CD8+depletion4-151 . | No. tumor progressors/mice injected (%)‡ . |
|---|---|---|---|
| CTLA-4− BM chimeras | C1498/B7-1 | No | 7/24 (29)4-153 |
| CTLA-4− BM chimeras | C1498/B7-1 | Yes | 7/7 (100) |
| CTLA-4+ BM chimeras | C1498/B7-1 | No | 21/23 (91) |
| CTLA-4+ BM chimeras | C1498/B7-1 | Yes | 7/7 (100) |
| Normal B6 mice | C1498/B7-1 | No | 7/7 (100) |
| CTLA-4− BM chimeras | C1498 | No | 7/7 (100) |
| CTLA-4+ BM chimeras | C1498 | No | 4/4 (100) |
| Normal B6 mice | C1498 | No | 7/7 (100) |
| Tumor hosts4-150 . | Tumor injected4-151 . | CD8+depletion4-151 . | No. tumor progressors/mice injected (%)‡ . |
|---|---|---|---|
| CTLA-4− BM chimeras | C1498/B7-1 | No | 7/24 (29)4-153 |
| CTLA-4− BM chimeras | C1498/B7-1 | Yes | 7/7 (100) |
| CTLA-4+ BM chimeras | C1498/B7-1 | No | 21/23 (91) |
| CTLA-4+ BM chimeras | C1498/B7-1 | Yes | 7/7 (100) |
| Normal B6 mice | C1498/B7-1 | No | 7/7 (100) |
| CTLA-4− BM chimeras | C1498 | No | 7/7 (100) |
| CTLA-4+ BM chimeras | C1498 | No | 4/4 (100) |
| Normal B6 mice | C1498 | No | 7/7 (100) |
Normal B6 or Thy1 congenic B6.PL-Thy1amice were conditioned with 1100 cGy of γ-radiation 1 day before intravenous infusion of 5.0 to 8.5 × 106 BM cells from CTLA-4− (−/−) or CTLA-4+ donors (either +/− or +/+).
Mice were injected subcutaneously with 1 × 106 tumor cells.
Mice were observed up to 70 to 96 days after bone marrow transplantation (approximately 40-60 days after tumor injection).
Significantly lower than in CTLA-4+ BM chimeras (P < .001) and normal B6 mice given C1498/B7-1 as well as CTLA-4− BM chimeras given C1498 (P < .005) (Fischer exact test).