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Efficient Quantification of HIV-1 Viral Isolates (Group M Subtypes A-G and Group O) by the Abbott LCx HIV RNA Quantitative Assay P. SWANSON, J. HACKETT JR*, and S. DEVARE. Abbott Labs., North Chicago, IL Viral strains, representing HIV-1 group M subtypes A-G and group O, provide a valuable tool to examine viral load assays and the quantification of non-clade B infections. The ABBOTT LCx HIV RNA Quantitative assay, which targets pol, was used to evaluate a well characterized panel of 39 virus isolates: 3A, 7B, 6C, 4D, 8E, 4F, 1G, 4 mosaics, and 2 group O. Thirty of the group M isolates were provided by Walter Reed Army Institute of Research (WRAIR). Each virus stock was initially adjusted to ~ 150,000 copies/ml followed by seven 5-fold dilutions in negative human plasma. Testing was performed on a total of 273 sample dilutions representing the assay dynamic range. In addition, sequence analysis of gag p24, pol, and env gp41 was performed to verify subtype and assess nucleotide mismatches at primer and probe binding sites. All group M subtypes and the 2 group O samples were quantitated by LCx®. For samples quantified with >50 copies/ml, the assay lower limit of quantitation, a high degree of correlation between expected versus actual LCx® log10 copies/ml was observed. For comparison, the Roche AMPLICOR HIV-1 Monitor version 1.5 ultrasensitive test, which targets the gag region, is being performed on all samples. The results showed that version 1.5 failed to quantify the group O viruses. Relative to AMPLICOR version 1.5, the high level of nucleotide conservation at the LCx® primer and probe binding sites is consistent with the ability of ABBOTT LCx to efficiently quantify HIV-1 group M and group O infections. Key Words: Genetic diversity, HIV-1 quantification, Probe-based assays |
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© 7th
Conference on Retroviruses and Opportunistic Infections, |