HIV-1 ACQUIRES RESISTANCE TO 2 CLASSES OF ANTIVIRAL DRUGS THROUGH HOMOLOGOUS RECOMBINATION

Genetic recombination contributes to the genomic heterogeneity of huma n immunodeficiency virus type 1 (HIV-1). In the present study, we demo nstrate that HIV-1 readily develops resistance to two classes of anti- HIV-1 drugs through in vitro genetic recombination involving large seg ments of the viral genome. Co-transfection of COS-7 cells with an HIV- 1 plasmid (pSUM13) carrying five mutations in the reverse transcriptas e (RT)-encoding region (A62V, V75I, F77L, F116Y, Q151M), conferring re sistance to multiple dideoxynucleoside analogs (ddNs), and another HIV -1 plasmid (pSUM431) carrying five mutations in the protease-encoding region (V32I, L33F, K45I, I84V, L89M), conferring resistance to protea se inhibitors such as KNI-272, readily produced HIV-1 carrying both se ts of mutations when propagated in MT-2 cells in the presence of azido thymidine (AZT) and KNI-272. The resultant HIV-1 variant was highly re sistant to both ddNs and KNI-272. Co-infection of MT-2 cells with HIV- 1(SUM13) carrying the RT mutations and HIV-1(SUM431) carrying the muta tions in the protease also generated HIV-1 with both sets of mutations when cultured with AZT and KNI-272. We also report here that the prob lematic artifactual recombination occurring during genetic analyses of heterogeneous nucleic acid sequences using polymerase chain reaction can be successfully obviated. (C) 1997 Elsevier Science B.V.