Structure-activity relationships at positions D and E or E and F of C5a antagonist peptides in combination
| Receptor Affinity | Antagonist Activity | ||||||
|---|---|---|---|---|---|---|---|
| No. | Peptide | n | −log IC50 ± S.E. | IC50a | n | −log IC50 ± SE | IC50b |
| μM | nM | ||||||
| 53 | AcF-[OPfFR] | 5 | 5.29 ± 0.22* | 5.2 | 3 | 5.28 ± 0.10* | 5210 |
| 54 | AcF-[OPf1NalR] | 3 | 5.51 ± 0.04* | 3.1 | N.D. | ||
| 55 | AcF-[OPfYR] | 3 | 4.16 ± 0.13* | 69.2 | N.D. | ||
| 56 | AcF-[OPdChaF(pCl)F] | 3 | 5.50 ± 0.09* | 3.2 | N.D. | ||
| 57 | AcF-[OPdChaF(pNH2)F] | 3 | 5.46 ± 0.10* | 3.5 | N.D. | ||
| 58 | AcF-[OPdChaFhF] | 3 | 5.17 ± 0.15* | 6.8 | N.D. | ||
| 59 | AcF-[OPdArgFR] | 3 | >1 mM | N.D. | |||
| 60 | AcF-[OPGmbTyrR] | 3 | 6.03 ± 0.08 | 0.93 | 2 | 6.17 ± 0.09* | 679 |
(pCl)F, para-chlorophenylalanine; (pNH2)F, para-aminophenylalanine; hPhe, homophenylalanine; mbTyr, metabenzyltyrosine; N.D., not determined; n, number of experiments; *, significant (P ≤ 0.05) difference from 1; Φ, no C5aR affinity up to 1 mM.
↵ a Concentration causing 50% inhibition of maximum binding of 125I-C5a to intact PMNLs.
↵ b Concentration causing 50% inhibition of myeloperoxidase release from PMNLs induced by 100 nM C5a.