TABLE 4.

Activation of fusion between Env-expressing cells and CD4-negative, CCR5-positive cells

Compound	Incubation time (min)	Area under the curve (arbitrary units) for HIV-1 Enva:
		AD8	JR-FL	JR-FL Y177R	JR-FL P183Y
NBD-556	5	<10	<10	36	<10
	10	<10	<10	23	<10
	30	<10	<10	106	<10
	60	<10	<10	105	<10
JRC-II-191	5	<10	<10	140	<10
	10	<10	<10	272	<10
	30	<10	<10	411	<10
	60	<10	<14	285	<10
DMJ-II-121	5	47	161	1,139	354
	10	94	171	659	335
	30	32	19	679	146
	60	<10	<10	168	12
JP-III-48	5	59	59	877	12
	10	69	12	884	29
	30	25	30	1,175	19
	60	20	29	746	15
BNM-III-170	5	47	74	1,567	76
	10	37	77	1,095	90
	30	66	27	1,334	58
	60	14	27	872	60

^aDifferent concentrations (0 to 100 μM) of the CD4mc were incubated with 293T cells expressing HIV-1 Env variants and the α peptide of β-galactosidase at 37°C for the indicated times. The cells were then washed and cocultivated with CD4-negative CCR5-positive Cf2Th-CCR5 cells expressing the ω peptide of β-galactosidase at 37°C in medium without the CD4mc. After 6 h, the extent of cell-cell fusion was assessed by measuring β-galactosidase activity in the cell lysates. The β-galactosidase activity was plotted as a function of the CD4mc concentration, and the area under the curve was measured for each time point. The results of a typical experiment out of two independent experiments are shown.