FIG. 4.

Sensitivity of detection of Ad2 and Ad41 mRNAs. An RT-PCR assay of Ad2 mRNA was performed with the E1A primer set, and an RT-PCR assay of Ad41 mRNA was performed with the hexon primer set. mRNA was recovered from infected cells after 5 to 7 days of incubation. (A) Lanes: 1 to 3, RT-PCR assay of Ad2 mRNA from A549 cells infected with 20, 2, and 0.2 IU; 4, RT-PCR assay of mRNA from noninfected A549 cells; 5, negative control; 6, positive control; 7 to 9, PCR assay of Ad2 mRNA from cells infected with 20, 2, and 0.2 IU; 10, PCR assay of mRNA in noninfected A549 cells; 11, negative control; 12, positive control. (B) Lanes: 1 to 7, RT-PCR assay or subsequent nested PCR assay of Ad41 mRNA from G293 cells infected with 10³, 10², 10, 1, 0.1, 0.01, and 0.001 IU at 7 days p.i.; 8, negative control; 9, positive control; 10 to 16, RT-PCR assay without RTase or subsequent nested PCR assay of mRNA from G293 cells infected with 10³, 10², 10, 1, 0.1, 0.01, and 0.001 IU at 7 days p.i.; 17, negative control; 18, positive control. A 100-bp DNA ladder was used as a molecular size marker (lane M). The detection sign (+ or −) was based on visual examination of the agarose gel for an amplicon of the correct size.