TABLE 2.

Comparison of plus- and minus-strand viral RNA levels in acute and persistently infected samples

Sample	Virus titera	No. of copies viral RNAb		Viral RNA strand ratio (plus:minus)c
		Plus strand	Minus strand
MP1/M (7 days)	2.1 × 108	4.5 × 104 (2.6 × 104–6.6 × 104)	6.0 × 102 (4.2 × 102–7.5 × 102)	75:1*
MP1/M (1 mo)	NDd	2.0 × 103 (1.3 × 103–2.8 × 103)	5.2 × 102 (3.9 × 102–6.5 × 102)	4:1
MP1/G8 (20 h)	1.1 × 106	4.6 × 105 (0.47 × 105–7.1 × 105)	7.7 × 103 (6.9 × 103–9.0 × 103)	60:1*
MP1/PI-G8 (passage 30)	3.4 × 104	6.3 × 103 (4.4 × 103–9.3 × 103)	1.5 × 102 (1.1 × 102–2.3 × 102)	42:1*

^aVirus titers are expressed as PFU per gram of muscle for muscle samples (M) or PFU per 10⁶ cells for G8 and PI-G8 cells. 

^bWhen quantitated by competitive RT-PCR, in vitro-transcribed control transcripts input at 4 × 10⁴ copies gave mean values of 2.1 × 10⁴ copies of plus-strand RNA (range, 1.8 × 10⁴ to 2.5 × 10⁴ copies) and 1.2 × 10⁴ copies of minus-strand RNA (range, 1.0 × 10⁴ to 1.6 × 10⁴ copies). Values shown in the table are the mean number of copies of the plus or minus strand expressed per microgram of total RNA from muscle or G8 cells. Values were determined from three independent samples, and the range is shown in parentheses. 

^c*, The number of copies of the plus strand was significantly different from that of the minus strand by the paired t test (α = 0.05). 

^dND, none detected.