Schematic for strategy to amplify viral cDNA and 2-LTR circles. (A) Schematic for the amplification of the final product of reverse transcription. This PCR identifies HIV-1 cDNA formed after the “second jump” of the reverse transcription process. (B) Schematic for the amplification of 2-LTR circles. A forward primer spanning the junction LTR-LTR was used in order to discriminate 2-LTR circles from products of autointegration. The arrows indicate the primers used in the reaction, and the dashed lines indicate the final PCR products.