TABLE 1.

Fabs 3674, 3670, and 3663 inhibit HIV-1 Env-mediated fusion^a

Env strain	IC50 (μg/ml)b for:
	bF-3674	mF-3674	bF-3670	bF-3663
LAV	8 ± 1	34 ± 6	20 ± 6	22 ± 8
IIIB	14 ± 3	23 ± 4	29 ± 6	81 ± 8
BaL	35 ± 9	68 ± 20	227 ± 138	253 ± 120
SF162	191 ± 51	159 ± 26	NA	NA
SF2	68 ± 13	103 ± 33	NA	NA

^aThe fusion assays were carried out as described (17) using diverse lab-adapted subtype B viruses.

^bNA, no activity: in the range of concentrations tested, inhibition of fusion was too weak to reliably determine an IC₅₀ value.