TABLE 2.

Detection of type D retroviruses in RT assays

Virus and no. of virus particlesa	RT activityb	Autorad resultc
SMRV
1.92 × 107	5,163 ± 228	+
1.92 × 106	574 ± 24	+
1.92 × 105	114 ± 10	+
1.92 × 104	79 ± 5	−
1.92 × 103	77 ± 5	−
SRV
8.25 × 105	547 ± 146	+
8.25 × 104	85 ± 9	+
8.25 × 103	65 ± 15	−

^aThe number of virus particles in 10 μl is indicated on the basis of the particle count obtained by electron microscopy by Advanced Biotechnologies Inc. The first sample in the case of SMRV represents a 1:100 dilution of the original sample, and the rest of the samples are 10-fold serial dilutions. In the case of SRV the first sample is undiluted virus and the rest of the samples are 10-fold serial dilutions. 

^bThe RT activity is counts per minute per 5 μl and is reported as the mean ± standard deviation for two RT assays which were done in duplicate, with each sample being spotted twice. 

^cAutorad, autoradiography. Results are based upon visual examination of an overnight exposure of the autoradiogram. The results are indicated as positive and negative and do not reflect the differences in the intensities of the positive signals.