TABLE 1

Homologous and heterologous competition binding in wt ORF74-HHV8 and [R208H;R212H]-ORF74

A whole panel of pharmacological different chemokines: agonists (CXCL1-3/GROα, -β, and -γ), and inverse agonists (CXCL10/IP10, CXCL12/SDF-1, and vCCL2/vMIP-II) were tested against 125I-CXCL1/GROα and 125I-CXCL10/IP10 in transiently transfected COS-7 cells as described under Materials and Methods. IC50 values ± S.E.M. are given for all tested chemokines. Fmut indicates the -fold change in affinity between mutant and wt receptor, calculated as IC50 ([R208H;R212H])/IC50 (ORF74-HHV8) for a given ligand measured against 125I-CXCL1/GROα (Ago. Fmut) and against 125I-CXCL10/IP10 (Inv. Fmut). Fligand indicates the -fold change in affinity for a given ligand depending upon applied radioligand, calculated as IC50 (125I-CXCL10/IP10)/IC50 (125I-CXCL1/GROα). The bold values are depicted as curves in Fig. 2.

125I-CXCL1/GROα as Radioligand
125I-CXCL10/IP10 as Radioligand
ORF74-HHV8
[R208H;R212H]
Ago. Fmut
 ORF74-HHV8
[R208H;R212H]
Inv. Fmut
 wt Fligand [R208H;R212H] Fligand
 IC50
n
 IC50
n
 IC50
n
 IC50
n
nM nM nM nM
Agonists
CXCL1/GROα 0.09 ± 0.02 a 16 0.52 ± 0.10 b 16 5.8 0.81 ± 0.14 7 111 ± 38 7 136 9.2 213
CXCL2/GROβ 0.22 ± 0.05 5 2.1 ± 0.36 3 9.2 1.6 ± 0.18 3 88 ± 17 3 55 7.2 43
CXCL3/GROγ 0.09 ± 0.01 5 1.7 ± 0.02 3 19 0.82 ± 0.16 3 69 ± 10 3 84 9.1 41
Inverse agonists
CXCL10/IP10 2.6 ± 0.71 3 5.2 ± 1.7 4 2.0 0.66 ± 0.11 c 15 0.73 ± 0.10 d 9 1.1 0.25 0.14
CXCL12/SDF1 13 ± 1.4 5 20 ± 5.2 2 1.5 11 ± 6.9 3 5.1 ± 2.2 3 0.4 0.87 0.25
vCCL2/vMIP-II
210 ± 111
4
87 ± 38
3
0.4
72 ± 8.8
7
38 ± 4.2
4
0.5
0.34
0.44

  • ↵ a 32 ± 6.3 fmol/105 cells, Bmax for the homologous competition binding.

  • ↵ b 1.3 ± 0.2 fmol/105 cells, Bmax for the homologous competition binding.

  • ↵ c 28 ± 2.7 fmol/105 cells, Bmax for the homologous competition binding.

  • ↵ d 37 ± 4.2 fmol/105 cells, Bmax for the homologous competition binding.