Detection of human immunodeficiency virus type 1 clinical isolates with reduced sensitivity to zidovudine and dideoxyinosine by RNA.RNA hybridization.

Abstract

A quantitative rapid assay to detect resistant clinical human immunodeficiency virus type 1 (HIV-1) strains remains an important medical goal. A system incorporating a quantitative RNA-RNA hybridization assay that measures the amount of intracellular HIV-1-specific RNA has been employed to detect the level of inhibition by nucleoside analogues in sensitive and resistant HIV-1 strains. The RNARNA hybridization assay readily distinguished previously published zidovudine (ZDV; 3'-azido-3'-deoxythymidine)-resistant isolates from ZDV-sensitive isolates of HIV-1. The 50% inhibitory concentration (ICso) of ZDV for HTLV-MB and sensitive clinical HIV-1 isolates is between 0.01 and 0.04 #tM. HIV-1 strains from three patients on long-term ZDV therapy displayed a greater than 20-fold increase in the ZDV IC50 compared to sensitive strains. The drug sensitivity system was confirmed by showing that mutations in the HIV reverse transcriptase gene from a ZDV-resistant isolate resulted in four amino acid changes (Leu-125 -+ Trp, Ile-142 -+ Val, Thr-215 --Tyr, and Pro-294 --Thr) including one change

Zidovudine treatment results in the selection of human immunodeficiency virus type 1 variants whose genotypes confer increasing levels of drug resistance

“…However, it is unlikely that highly resistant viruses that contain a mutation at codon 41 will also contain a Phe at codon 215. Other mutations in HIV RT have been implicated in zidovudine resistance although none has been introduced into defined genetic backgrounds to prove their contribution (Gingeras et al, 1991 ;Japour et al, 1991;Sheehy & Desselberger, 1993). In this study, variation in RT was also observed resulting in amino acid substitutions.…”

In vitroSelection of Human Immunodeficiency Virus Type 1 Resistant to Ro 31-8959 Proteinase Inhibitor

“…Experimental evidence showing the appearance, both in vitro and in vivo, of HIV-1 strains resistant to nucleoside analogues has been repeatedly reported (Larder and Kemp 1989;Larder et al, , 1991BOUCher et al, 1990;Land et al, 1990;Clair et al, 1991;Japour et al, 1991;Dianzani et al, 1992) but, so far, no data are available on the possibility of obtaining HIV-1 mutants resistant to proteinase inhibitors. Here we show that it is possible readily to select HIV-1 strains resistant to an inhibitor of HIV proteinase simply by growing the virus in the presence of the drug.…”

Antiviral Synergy between Inhibitors of HIV Proteinase and Reverse Transcriptase

“…Furthermore, prolonged treatment with these compounds is likely to promote the emergence of virus resistant to their antiviral effects. This has been well documented for AZT (Larder et al, 1989;Boucher, et aI., 1990;Richman et al, 1990;Lopez-Galindez et st., 1991) and has been reported for ddl (Japour et al, 1991;St. Clair et al, 1991;Fitzgibbon et al, 1992).…”