Table 1. Binding parameters for different CD4 miniproteins obtained using competition experiments.

S.D. values were 15% of the mean in ELISA and less than 5% in fluorescence polarization assays.

	IC50 (M)			KI (M)
Competitor	HxB2*	LAI†	LAI‡	SF162†	LAI†
CD4M9	1.6×10−6	1.1×10−6	3.6×10−7	4.6×10−7	6.9×10−7
[Tpa1]CD4M9	2.2×10−7	8.4×10−8	2.6×10−8	2.7×10−8	5.7×10−8
[Val27]CD4M9	9.6×10−7	6.1×10−7	3.2×10−7	1.4×10−7	5.0×10−7
[Bip23]CD4M9	9.0×10−7	3.4×10−7	9.7×10−8	1.7×10−7	3.1×10−7
CD4M32	3.8×10−8	3.7×10−9	2.3×10−8	3.8×10−9	1.1×10−8
CD4M33	7.5×10−9	2.6×10−9	1.4×10−8	3.2×10−9	5.3×10−9
sCD4	2.0×10−9	2.0×10−9	9.0×10−9	2.8×10−9	4.5×10−9
CD4M33-Fl	1.2×10−9

* Values obtained using ELISA.

† Values obtained using fluorescence polarization experiments in 384-well plates.

‡ Values obtained using fluorescence polarization assays on Beacon 2000 spectrophotometer.