Detection of HIV-1 DNA by polymerase chain reaction incorporation of digoxigenin-11-dUTP and hybridization to immobilized probes.

We have developed a new non-isotopic polymerase chain reaction (PCR) based method for the detection of the human immunodeficiency virus type 1 (HIV-1) DNA in clinical samples. In this method a two step PCR is used to amplify and label HIV-1 DNA segments by incorporation of digoxigenin-11-dUTP (dig-dUTP). Digoxigenin labelled amplified products are hybridized to membrane immobilized complementary DNA probes. Hybridization is detected non-radioactively by incubating the filters with antidigoxigenin antibody conjugated with alkaline phosphatase followed by a standard phosphatase assay. With this method the detection limit was between 1 and 10 HIV-1 DNA copies in a background of 1 microgram of human genomic DNA. Furthermore, we were able to detect HIV-1 DNA in 41 out of 41 HIV-1 antibody positive individuals while 10 out of 10 HIV-1 seronegative individuals gave consistently negative results. Our data indicate that this simple non-isotopic technique is sensitive and specific for the detection of HIV-1 DNA in clinical samples and can constitute a good alternative to other non-isotopic methods described to date.