Table 2.
Comparison of the properties of H4 receptor ligands in native human monocytes
| Histamine | 4-Methylhistamine | UR-PI376 | Clobenpropit | VUF8430 | ST-1006 | |
|---|---|---|---|---|---|---|
| IL-12 down-regulation | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| pEC50 published | 7.7 ± 0.10 | 7.4 ± 0.10 | 7.5 ± 0.01 | 7.7 ± 0.10 | 7.3 ± 0.10 | 8.95 ± 0.29 |
| pEC50 determined in monocyte assay (see Figure 2 for data) | 6.5 ± 0.18 | 6.9 ± 0.24 | 5.7 ± 0.32 | 6.5 ± 0.28 | 6.8 ± 0.18 | 6.7 ± 0.29 |
| IL-12 down-regulation blocked by antagonism of | ||||||
| H4R | Partially | Partially | Partially | Partially | Partially | ✓ |
| H2R | Partially | Partially | X | X | X | X |
The potency of H4 receptor ligands with regard to IL-12p70 down-regulation and the modulation of their effect by H2 receptor (H2R) and H4 receptor (H4R) antagonists are shown.
Potencies are shown as pEC50 values and are expressed as means ± SEM.