AEGiS-14IAC: Evolution of viral populations in a rapid progressor dually infected with two distinct HIV-1 subtype C viruses.

14th International AIDS Conference

Barcelona, Spain - July 7-12, 2002

Evolution of viral populations in a rapid progressor dually infected with two distinct HIV-1 subtype C viruses.

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. A10028)

Grobler J, Papathanasopoulos MA, Rademeyer C, Cilliers T, Gray C, Ramjee G, Abdool-Karim S, Morris L, Williamson C
University of Cape Town, Cape Town, South Africa

BACKGROUND: We have been monitoring a cohort of female sex workers from KwaZulu/Natal, South Africa and have detected dual infection in one woman who died within two years from seroconversion. This study aims to monitor viral evolution before and after seroconversion, based on changes in the env and gag genes.

METHODS: Plasma samples were collected prior to seroconversion, and 1, 8, 17 and 19 months post seroconversion. A 504bp C2-V3 env fragment was amplified and diversity assessed by heteroduplex tracking assays (HTA) and sequencing. Phenotype was predicted by V3 amino acid sequence in addition to tissue culture. Sequencing of the p17 gag region was carried out to confirm dual infection. Phylogenetic and recombination analysis was performed.

RESULTS: Two distinct viral populations, consisting of a major group (90%) and a minor group (10%), were present prior to seroconversion. Env and gag sequencing confirmed two independent phylogenetic lineages within subtype C, which differs by 11% in the C2-V3 and 8% in p17 region. There were no changes in viral populations 1 month after seroconversion. Recombination between the major and minor group was identified by 8 months and became the dominant population at 19 months. The predicted phenotype of the minor group, prior to seroconversion, switched from NSI to SI by 17 months and by 19 months accounted for 30% of the total population. Coreceptor studies confirmed the transition from R5 to R5X4 phenotype. The major population at transmission could not be detected at 18 months.

CONCLUSIONS: This individual was infected with two HIV-1 subtype C strains prior to seroconversion. The dominant virus at transmission was replaced over time with the recombinant; and the minor population at transmission became SI-like within a year of infection. Further studies need to be done to determine the frequency of dual infection and the implications thereof on rapid disease progression.

Keywords: AEGIS, HIV-1, Genes, gag, Evolution, HIV-1 Reverse Transcriptase, Amino Acid Sequence, Phylogeny, Recombination, Genetic, South Africa, Human, Female, virology, genetics

020707
A10028