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Semi-quantitative HIV-1 mutation analysis using the Murex-Innogenetics LiPA HIV-1 RT assay.
Sheridan F; Parker D; Shuurman R; De Graaf L; Tijnagel J; Boucher C;
December 30, 1998
Int Conf AIDS. 1998;12:787 (abstract no. 41225). Unique Identifier :

BACKGROUND: A line probe assay has been developed for the simultaneous detection of the common mutations of the reverse transcriptase gene of HIV-1 which have been associated with resistance to zidovudine (AZT), lamivudine (3TC), didanosine (ddI) and zalcitabine (ddC). The assay detects the presence of both consensus wild type and resistant genotypes at codons 41, 69, 70, 74, 75, 184 & 215. The test is based on the amplification of the reverse transcriptase gene using biotinylated primers followed by reverse hybridisation of the amplicon with a series of complementary probes bound to a nitro-cellulose strip. Signal generation is accomplished using a streptavidin-alkaline phosphatase conjugate and BCIP/NBT substrate. We assessed the ability of LiPA HIV-1 RT to determine if an increase in the proportion of resistant virus for a particular codon correlates with increase in viral load. METHODS: Plasma samples from 19 patients were tested using the Murex-Innogenetics HIV-1 RT LiPA assay and Roche Amplicor HIV-1 Monitor viral load test. A semi-quantitative estimate of LiPA signal intensity at each codon was determined. RESULTS: The results show a correlation between an increasing viral load and the emergence of mutations which are associated with resistance to AZT. LiPA analysis illustrates the presence of a mixture of mutant and wild type consensus sequence in the plasma virus population. The subsequent outgrowth of mutant virus as the apparently dominant quasi-species as measured by relative LiPA signal intensity correlated with an increase in the viral load. CONCLUSIONS: Our results suggest that the signal intensity of both wild type and resistant lines on the LiPA strip may be used to determine the relative proportions of wild type and mutant virus present in the total virus population. The relative increase in signal intensity of the mutant probe compared to the wild type probe correlates with outgrowth of the resistant species which in turn accounts for an increase in viral load.

MEETING ABSTRACTS Anti-HIV Agents/PHARMACOLOGY Drug Resistance, Microbial/GENETICS Human HIV Infections/BLOOD/*VIROLOGY HIV-1/*ENZYMOLOGY/GENETICS HIV-1 Reverse Transcriptase/*GENETICS *Mutation Nucleic Acid Hybridization Reagent Kits, Diagnostic Reverse Transcriptase Inhibitors/PHARMACOLOGY Zidovudine/PHARMACOLOGY