CD4-independent use of the CCR5 receptor by sequential primary SIVsm isolates

Retrovirology

Table 1 Comparison of the capacity to infect NP-2 cells by isolates on mPBMC or hPBMC.

Origin of cells for virus isolation	Isolate^a			NP-2/CD4/CCR5 syncytia^b	NP-2/CCR5 syncytia	NP-2/CCR5+PBMC virus production ^c RT (pg/ml)
	Monkey	Time PI (months)
mPBMC	D24	0.5		++++	+++	>1000
		3		++++	+	803
		10	§	+++	-	560
	C73	5	§	++++	++	>1000
		7	§	++++	++	649
		18		++++	+	450
	C68	0.5	#	++	-	526
		30	#	++	-	674
		53	#	++	-	78
	B173	0.5		++++	+++	998
		39		++++	+	827
hPBMC	D24	0.5		+++	-	>1000
		3		++	-	713
		12	§	-	-	<50
	C73	0.5	§	++	-	573
		3	§	++	-	161
		18		++++	-	>1000
	C68	0.5		++++	-	<50
		3	§	++++	-	>1000
		30		++++	-	741
		53		++++	-	762
	B173	0.5		++++	+/-	>1000
		90	§	++	-	>1000
		39		+	-	85

^a Cells were infected with virus stocks containing 2.7–3.5 log10 pg RT/well except for indicated (#) isolates that were infected with 1.9–2.3 log10 pg RT/well. §Isolates that could not be obtained on corresponding time-points when isolating viruses on mPBMC and hPBMC, respectively. PI, time for virus isolation post infection.
^b Induction of syncytia was observed in light microscope 5 and 7 days after infection. -, no syncytia; +, 10–20 syncytia per well; ++, syncytia covering 20–50% of the wells; +++, syncytia covering 50–90% of the wells; ++++, syncytia covering >90% of the wells
^c Virus production was measured six days after start of cocultures with human PBMC (hPBMC). Values are means of two independent infections in duplicate wells. Supernatant culture fluids were collected at day 7 and production of RT was analyzed. Supernatants were undiluted in the RT assay and therefore values above 1000 pg RT/ml cannot be separated. Cut-off detection level was 50 pg RT/ml

ISSN: 1742-4690