TABLE 2.

Effect of exogenous proinflammatory cytokines and cathepsin D on MAGI plaque formation

Treatment	Concn (ng/ml)	No. of MAGI plaquesa
IL-1βb	10	0
	5	3
	1	0
	0.5	0
	0.1	0
IL-6b	1	NDc
	0.5	0
	0.1	0
	0.05	0
	0.01	0
TNF-αb	100 pg/ml	1
	50 pg/ml	4
	25 pg/ml	5
	12.5 pg/ml	0
	6.25 pg/ml	2
Cathepsin Dd	20 μg/ml	43
	10 μg/ml	31
	5 μg/ml	47
	2.5 μg/ml	45
	1.25 μg/ml	50
Background		3 ± 1.3f
Positive controle		54 ± 2.9f

^aThat is, the number of MAGI plaques above the background level. The data are expressed as the averages of duplicate wells for single cytokine treatments and of quadruplicate wells for combined treatments.

^bIL-1β, IL-6, and TNF-α were separately diluted into PBS at or above reported concentrations in vaginal lavage samples from HIV-1-infected women (4, 39; Villanueva et al., Abstr. Microbicides 2000 NIH Conf.), and the effect on the formation of MAGI plaques was tested in the absence of virus.

^cND, not determined. A total of 1 ng of IL-6/ml inhibited the growth of R5-MAGI cells and resulted in sloughing of the cells from the wells.

^dHIV-1_Ba-L (30 TCID₅₀) was pretreated for 30 min at 37°C with concentrations of cathepsin D (diluted in PBS) known to enhance HIV-1 infection before being added to the MAGI cultures.

^eHIV-1_Ba-L (30 TCID₅₀) was added to PBS as a positive control.

^fMean number of plaques ± the standard deviation.