IFNγ Downregulates SCF Receptors While Not Affecting kd
| Cell Type . | ECFC Purity . | kd . | No. of Receptors Per Cell . | No. of Receptors Per ECFC . |
|---|---|---|---|---|
| . | (%) . | (nmol/L) . | . | . |
| Control | ||||
| 1 | 49 ± 4 | 0.139 | 18,984 | 38,744 |
| 2 | 53 ± 7 | 0.129 | 24,116 | 45,502 |
| 3 | 36 ± 5 | 0.133 | 24,136 | 67,046 |
| Mean | 46 ± 7 | 0.134 ± 0.004 | 22,412 ± 2,424 | 50,431 ± 12,068 |
| IFNγ | ||||
| 1 | 51 ± 4 | 0.147 | 14,046 | 27,541 |
| 2 | 48 ± 1 | 0.119 | 16,100 | 33,543 |
| 3 | 37 ± 4 | 0.135 | 16,831 | 45,489 |
| Mean | 45 ± 6 | 0.134 ± 0.011 | 15,659 ± 1,179 | 35,524 ± 7,460 |
| P value | >.78 | >.95 | .019 | .047 |
| Cell Type . | ECFC Purity . | kd . | No. of Receptors Per Cell . | No. of Receptors Per ECFC . |
|---|---|---|---|---|
| . | (%) . | (nmol/L) . | . | . |
| Control | ||||
| 1 | 49 ± 4 | 0.139 | 18,984 | 38,744 |
| 2 | 53 ± 7 | 0.129 | 24,116 | 45,502 |
| 3 | 36 ± 5 | 0.133 | 24,136 | 67,046 |
| Mean | 46 ± 7 | 0.134 ± 0.004 | 22,412 ± 2,424 | 50,431 ± 12,068 |
| IFNγ | ||||
| 1 | 51 ± 4 | 0.147 | 14,046 | 27,541 |
| 2 | 48 ± 1 | 0.119 | 16,100 | 33,543 |
| 3 | 37 ± 4 | 0.135 | 16,831 | 45,489 |
| Mean | 45 ± 6 | 0.134 ± 0.011 | 15,659 ± 1,179 | 35,524 ± 7,460 |
| P value | >.78 | >.95 | .019 | .047 |
Day-5 ECFCs, at a concentration of 1 × 106/mL, were cultured with and without 2,500 U/mL IFNγ for 24 hours at 37°C. The cells were then incubated with increasing concentrations of 125I-rhSCF (0 to 0.5 nmol/L) for 48 hours at 0°C, and specific binding was determined. The kd and number of receptors were calculated by Scatchard analysis. Data are expressed as means ± SD and significance was calculated using the paired t-test.