Effect of Cytotoxicity Mutations on the Ability of Donor T Cells to Prevent Marrow Graft Rejection
| T-Cell Phenotype . | No. Rejected/No. Evaluated (%) . | ||||
|---|---|---|---|---|---|
| 5 × 104 CD8 . | 2 × 105 CD8 . | 8 × 105 CD8 . | 2-3 × 106 CD8 . | 1-2 × 107 CD8 . | |
| Wild-type* | 22/34 (65) | 6/23 (26) | 0/15 (0) | ||
| Fas-ligand–defective (gld) | 15/15 (100) | 0/5 (0) | 0/5 (0) | ||
| Granzyme B-deficient | 14/14 (100) | 1/5 (20) | 0/5 (0) | ||
| Perforin-deficient† | 4/4 (100) | 8/9 (89) | 6/8 (75) | 4/8 (50) | 0/4 (0) |
| Perforin-deficient‡/gld | 5/5 (100) | 5/5 (100) | 5/5 (100) | 11/11 (100) | |
| Perforin-deficient†/gld | 5/5 (100) | ||||
| T-Cell Phenotype . | No. Rejected/No. Evaluated (%) . | ||||
|---|---|---|---|---|---|
| 5 × 104 CD8 . | 2 × 105 CD8 . | 8 × 105 CD8 . | 2-3 × 106 CD8 . | 1-2 × 107 CD8 . | |
| Wild-type* | 22/34 (65) | 6/23 (26) | 0/15 (0) | ||
| Fas-ligand–defective (gld) | 15/15 (100) | 0/5 (0) | 0/5 (0) | ||
| Granzyme B-deficient | 14/14 (100) | 1/5 (20) | 0/5 (0) | ||
| Perforin-deficient† | 4/4 (100) | 8/9 (89) | 6/8 (75) | 4/8 (50) | 0/4 (0) |
| Perforin-deficient‡/gld | 5/5 (100) | 5/5 (100) | 5/5 (100) | 11/11 (100) | |
| Perforin-deficient†/gld | 5/5 (100) | ||||
Irradiated (550 cGy) bm1 recipients were transplanted with grafts containing 5.0 × 106 B6-Ly5.1 T-cell–depleted marrow cells and the indicated numbers of CD8-enriched LN cells from wild-type B6 donors or from donors with mutations in T-cell cytotoxicity. Data indicate the proportions (percentages) of survivors with less than 20% Ly5.1-positive granulocytes in the blood when last tested at 1 to 3 months after transplantation. All but 7 engrafted recipients were observed for at least 2 months after transplantation and had 35% to 100% (mean, 93.5%) donor marrow-derived granulocytes when last tested before being euthanized. Only 1 engrafted recipient had less than 50% donor marrow-derived granulocytes at the time of euthanasia. Recipients with rejection had 0% to 13% (mean, 2.52%) donor marrow-derived granulocytes when last tested before being euthanized. Rejection occurred in 39 of 40 (97%) recipients transplanted with marrow containing no added T cells. Data are summarized from a series of seven experiments.
In four experiments in which control CD8 cells were enriched by immunoadherent negative selection, rejection occurred in 14 of 24 (58%), 2 of 13 (15%), and in 0 of 5 (0%) recipients transplanted with grafts respectively containing 5.0 × 104, 2.0 × 105, or 8.0 × 105 T cells. By logistic regression, 6.8 × 104 LN CD8 cells were sufficient to prevent rejection in 50% of the recipients. In three experiments in which control CD8 cells were enriched by immunomagnetic positive selection, rejection occurred in 8 of 10 (80%), 4 of 10 (40%), and in 0 of 10 (0%) recipients transplanted with grafts respectively containing 5.0 × 104, 2.0 × 105, or 8.0 × 105 T cells. By logistic regression, 1.66 × 105 LN CD8 cells enriched by positive selection were needed to prevent rejection in 50% of the recipients (P = .04 as compared with LN CD8 cells enriched by negative selection). These results suggest that binding of immunomagnetic particles to CD8 molecules had a small effect on the ability of CD8 cells to prevent rejection, but this effect was easily overcome by increasing the number of CD8 cells added to the graft.
This strain had perforin expression disrupted by an insertion at the exon 3 BstEII site and was fully backcrossed to B6.
This strain had perforin expression disrupted by an insertion at the exon 3 Sph I site and was backcrossed to B6 for 8 to 10 generations.