Table 3. DNA methylation and quantitative analysis of B19V nucleic acids in transfection experiments.
| Transfection | Sample | B19 DNA | Met Index | B19 RNA | RNA/DNA |
| pB19-M20, Unmethylated | 02 hpt | 1.44E+06 | <0.001 | 8.32E+05 | 5.78E−01 |
| 24 hpt | 1.49E+06 | <0.001 | 3.86E+07 | 2.60E+01 | |
| 48 hpt | 5.49E+05 | <0.001 | 1.17E+10 | 2.13E+04 | |
| 72 hpt | 1.23E+05 | <0.001 | 1.34E+10 | 1.09E+05 | |
| pB19-M20, Methylated | 02 hpt | 1.14E+06 | 0.969 | 2.42E+04 | 2.12E−02 |
| 24 hpt | 1.09E+06 | 0.972 | 1.99E+06 | 1.82E+00 | |
| 48 hpt | 1.03E+06 | 0.955 | 2.19E+09 | 2.13E+03 | |
| 72 hpt | 2.56E+05 | 0.929 | 1.58E+09 | 6.18E+03 |
UT7/EpoS1 cells were transfected with 1 µg/106 cells of either unmethylated or M.SssI methylated B19V DNA, excised from pB19-M20 plasmid, and samples collected at 2, 24, 48, 72 hours post-transfection (hpt). Quantitative analysis was carried out for the determination of the amounts of viral DNA and total viral RNA from cell fractions (copies/104 cells). Methylation index was calculated by parallel amplification with both MSP primer pairs on bisulfite-modified DNA and is expressed as ratio of methylated over total viral DNA.