Palmer S, Maldarelli F, Kearney M, Kottilil S, Lucey D, Metcalf J, Rock D, VanHoutte M, Michels L, Hertogs K, Mellors J, Coffin J; Conference on Retroviruses and Opportunistic Infections.

Abstr 10th Conf Retrovir Oppor Infect Feb 10 14 2003 Hynes Conv Cent Boston Mass USA Conf Retrovir Oppor Infect 10th 2003 Boston Mass. 2003 Feb 10-14; 10: abstract no. 493.

HIV Drug Resistance Prgm, NCI, NIH, Frederick, MD

BACKGROUND: Characterization of the genetic diversity of HIV-1 in patients (pts) can provide insight into the mechanism of generation of diversity and resistance. We therefore studied the genetics of a conserved region of the genome using a limiting-dilution RT-PCR technique.METHODS: Plasma samples were obtained from 3 pts between 2 and 9 wks after infection or from chronically-infected pts over a period of 2 yrs. Multiple sequences were obtained using limiting-dilution RT-PCR amplification of the p6 region of gag, pro, and the first 900 nucleotides of RT. Phylogenetic analyses were performed to determine genetic relatedness among amplicons. Rates of accumulation of mutations were calculated from the estimated infection date and the estimated turnover rate of infected cells.RESULTS: Virus populations from all pts were at least 5% different from one another and from standard laboratory viruses in the region analyzed. The 3 pts with early infection had nearly monomorphic viral populations: a total of 19 substitutions in 102,179 nucleotides sequenced, corresponding to an average variation of ~0.02%, not significantly greater than assay background. The rate of accumulation of mutations in these pts was much less than expected from the estimated number of replication cycles since infection and the mutation rate of HIV-1. By contrast, sequences from pts with chronic infection, showed an average intra-patient variation of ~2% and evidence of extensive recombination. Control experiments excluded recombination during the assay. The diversity and genetic composition of the virus populations remained constant for at least 2 yrs. In pts starting antiretroviral therapy, there was no change in the genetic composition of the HIV-1 population even after > 100-fold decreases in plasma HIV-1 RNA.CONCLUSIONS: Our technique provides additional insight into the evolution of genetic diversity of HIV-1 populations. Pts with early infection had virtually monomorphic virus populations, implying strong purifying selection. Although much greater genetic diversity was evident in chronic infection, the virus population exhibited a high level of genetic stability over years and after initiation of therapy resulting in 100-fold reductions in viremia. These results suggest a large replicating HIV-1 population in infected persons.

Publication Types:

• Meeting Abstracts

Keywords:

• Base Sequence
• Genes, gag
• HIV-1
• Humans
• Mutation
• Recombination, Genetic
• Selection (Genetics)
• Variation (Genetics)
• Viremia
• genetics

Other ID:

• GWAIDS0021478

UI: 102261102

From Meeting Abstracts