TABLE 1.

Fusogenic activities of each Env with cells expressing endogenous coreceptors

Cladeb	Isolate (World Health Organization)b	MT-2 assay phenotypeb,c	Relative Env-mediated fusion against cells expressing endogenous coreceptors (%)a
			PBMCs	Macrophagesd	Jurkat
Prototypic
B	LAV	SI	100	14	100
B	Ba-L	NSI	72	100	0
B	89.6	SI	99	287	274
Primary
A	92UG037.8	NA	2	17	0
B	91US005.11	NSI	74	319	10
	92US711.14	NSI	5	3	0
	91US712.4	SI	2	25	0
	92US715.6	NSI	98	205	2
	92US716.6	NSI	54	152	2
	92HT593.1	NSI	160	104	71
	92TH014.12	NSI	94	109	2
	92BR020.4	NSI	100	74	1
C	93MW965.26	NSI	98	88	1
	92BR025.9	NSI	41	91	1
D	92UG021.16	SI	74	30	74
	92UG024.2	SI	171	104	123
	93ZR001.3	NA	107	109	78
E	93TH966.8	NSI	19	6	0
	92TH022.4	NSI	95	107	6
F	93BR029.2	NA	25	51	0
G	92UG975.10	NSI	22	29	2
F/B	93BR019.10	NA	58	273	6

^aLAV Env fusion with PBMCs and Jurkat cells was arbitrarily set at 100%, as was Ba-L Env fusion with macrophages. The fusion exhibited by each Env against a particular cell type was scored relative to these standards. 

^bFrom reference 26. 

^cSI, syncytium-inducing; NSI, non-syncytium-inducing; NA, not available. 

^dEnv effector cells (10³) were mixed with 10⁵ macrophages expressing vaccinia virus-encoded CD4.