Table 2.
Effect of T cell depletion on induction of systemic protective immunity by NXS2 neuroblastoma cells transiently secreting scIL-12
| Vaccine | Depletion* | Bone marrow† metastasis | Liver‡ metastasis | Liver weight,§ mg |
|---|---|---|---|---|
| None | None | 2,2,2,2 | 4,4,4,4 | 3112 ± 105 |
| NXS2 S empty pl. | None | 2,2,2,1,1,0 | 4,3,2,1,1,1 | 2465 ± 137 |
| NXS2 H2A scIL12 | None | 0,0,0,0,0,1 | 0,0,0,0,0,1 | 1063 ± 29 |
| NXS2 H2A scIL12 | CD4 | 1,1,0,0 | 3,3,0,0 | 1510 ± 124 |
| NXS2 H2A scIL12¶ | CD8 | 2,2,1,1 | 4,4,3,2 | 2408 ± 299 |
| NXS2 H2A scIL12¶ | CD4 + CD8 | 2,2,2,1 | 4,4,2,1 | 2395 ± 436 |
Mice were injected s.c. with 2 × 106 NXS2 cells genetically engineered to secrete scIL-12 using histone H2A (H2A) and challenged by a lethal intravenous injection of 5 × 104 NXS2 wild-type cells 7 days after initial inoculation.
T cells were depleted by i.p. injection of 500 μg of anti-CD4 and anti-CD8 antibodies at days 0, 7, 14, and 21.
Bone marrow metastases were staged according to results obtained by high and low sensitivity tyrosine hydroxylase RT-PCR as described in Materials and Methods.
Liver metastases were staged according to the percentage of metastatic liver surface: 0, 0%; 1, <0–25%; 2, 25–50%; 3, 50–75%; 4, >75%.
Liver weight was determined on fresh specimen and expressed as mean values ± SE.
Differences in bone marrow staging, liver metastasis, and liver weights between CD8-depleted groups and the nondepleted control group were statistically significant (P < 0.05).