TABLE 1.

Molt4 and SupT1 infection and coreceptor use by R5 strains^a

HIV-1 strains	Infectivity
	TCID50/ml		FFU/ml
	On SupT1	On Molt4	On U87/CD4 cells			On CCC/CD4 cells
			CXCR4, CCR1, CCR2b	CCR3	CCR5	CCR8	GPR-15	STRL-33	GPR-1, CX3CR1, D6
C3	1.7	1	—b	—	3.5 × 104	—	—	—	—
C3/SupT1	1.7 × 101	1.7 × 101	—	—	7 × 105	—	—	20	—
JRCSF	—	—	—	—	4 × 103	—	—	—	—
E80	1	1	—	3 × 102	2.4 × 104	—	—	—	—
E80/SupT1	1.7 × 101	1.7 × 101	—	6 × 102	5 × 105	—	—	—	—
BR92	1 × 101	1.7	—	—	2.4 × 105	—	3.5 × 102	10	—
BR92/SupT1	1.7 × 103	1.7 × 102	—	—	2 × 106	—	5 × 102	102	—
BR53	—	—	—	—	5 × 103	—	—	—	—
BR90	—	—	—	—	1.2 × 105	—	—	—	—
SL2	—	—	—	4 × 102	3 × 105	—	3 × 102	10	—
SL3	—	—	—	—	2.2 × 104	—	—	—	—
SL4	—	—	—	—	2 × 103	—	—	—	—
JRFL	—	—	—	2 × 101	7 × 103	—	—	—	—
ADA	—	—	—	6 × 102	7 × 104	102	2 × 102	—	—

^aU87 cells stably expressing human CD4 and either human CCR1, CCR2b, CCR3, CCR5, or CXCR4 as well as CCC/CD4 cells transfected with expression vectors encoding either human CCR8, GPR-15, STRL-33, GPR-1, CX3CR1, or D6 (49) were seeded into 48-well trays (Costar) at 6 × 10⁴ cells per well. After 24 h, the cells were challenged with 100 μl of serial dilutions of NSI HIV-1 strains for 3 h at 37°C. After 4 days, the wells were fixed and immunostained as previously described (18). The number of positively stained foci was estimated by light microscopy, and the average number of FFU per milliliter was calculated from duplicate wells. 

^b—, no infection detected on SupT1 or Molt4 cells, and <10 FFU/ml on U87/CD4 or CCC/CD4 cells.