BOOSTER PCR - EVALUATION OF AN IMPROVED METHOD FOR AMPLIFICATION OF A FEW HIV-1 PROVIRAL DNA-SEQUENCES

A biphasic polymerase chain reaction designed as booster PCR for the detection of human immunodeficiency virus type-I (HIV-1) was evaluated in samples containing a very low number of target DNA. We examined DNA samples obtained from cronically infected H9/HTLV-III B cells and purified plasmidic DNA containing the entire HIV-1 genome. By using booster PCR we detected HIV-1 DNA sequences up to 5 infected cells in samples containing about 2 mug of genomic DNA, and up to 1 copy of plasmidic DNA in samples containing about 0.5 mug of genomic DNA. Otherwise by using standard PCR HIV-DNA up 100 infected cells and up to 20 copies from plasmidic DNA could be detected. Our experiments in amplification of HIV-1 proviral DNA have demonstrated that booster PCR enhances sensitivity of detection of standard PCR in small quantities of target sequences at least 20-fold with no loss of specificity.