Table 1.

Competition of anti-gp120 mAbs with X5 for gp120_JR-FL and gp120_89.6

mAb	Epitope	Env	Competition
			−sCD4	+sCD4
17b	CD4i	89.6	+	++
17b	CD4i	JR-FL	+	++
CG10	CD4i	89.6	0	++
CG10	CD4i	JR-FL	0	+++
A32	CD4i(C1–C4)	89.6	−−−	−
A32	CD4i(C1–C4)	JR-FL	−−	−−
48d	CD4i	89.6	+	+
23e	CD4i	89.6	+	+
21c	CD4i	89.6	+	+
F91	CD4bs	JR-FL	+	NA
IgG1b12	CD4bs	JR-FL	+	NA
19b	V3	JR-FL	0	0
G3-136	V2	JR-FL	0	0
MAG45	C1	JR-FL	0	0
C11	C1–C5	JR-FL	0	0
2G12	C3/V4	JR-FL	0	0
G3–519	C4	JR-FL	0	0
X5	CD4i	89.6	+++	+++

Gp120_JR-FL was captured by the anti-gp120 Ab D7324 and incubated with X5 (5 μg/ml) and various antibodies at different concentrations in absence or presence of sCD4 (2 μg/ml), and IgG Fc of the bound antibodies was detected with goat anti-mouse or anti-human IgG Fc alkaline phosphatase conjugate. Gp120_89.6 was directly coated on 96-well plates and incubated with biotinylated X5 (0.5 μg/ml) and various antibodies, and the amount of bound X5 was detected by using streptavidin-HRP. +, Denotes some competition; ++, significant competition; +++, complete displacement; −, various degrees of enhancement; 0, lack of measurable effects; NA, not applicable.