AEGiS-14IAC: Phylogenetic variation of the ltr and nef genes in HIV infected Indians in KwaZulu Natal.

14th International AIDS Conference

Barcelona, Spain - July 7-12, 2002

Phylogenetic variation of the ltr and nef genes in HIV infected Indians in KwaZulu Natal.

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. C10729)

Moodley P, Smith AN, Madurai S, Tarin M, Cassol S
Nelson R Mandela School Of Medicine, Durban, South Africa

BACKGROUND: Clade C is endemic in South Africa with KwaZulu Natal having the highest seroprevalence of 36% in black antenatal clinic attendees. The prevalence in local Indians appears to be sporadically increasing. Compared to the predominant heterosexual spread of HIV in South Africa, the epidemic in India is due to multiple mechanisms of transmission. Clade C in India shares high homology with South African isolates. This may have implications for selective transmission in different ethnic groups. The ltr and nef genes raise the possibility of identifying variants with different replicative properties, which may influence viral transmissibility, pathogenicity and host immune responses. The ltr gene has two NF-kB binding sites critical for the initiation of transcription. A third site has been reported in subtype C isolates from South Africa and occassional Indian isolates. The nef gene produces immunogenic proteins which downregulates expression of CD-4 receptors, increasing the activity of NF-kB by an unknown mechanism thus increasing viral infectivity. Little is known of the phylogenetic variation of the ltr and nef gene in South African Indians.

METHODS: Whole blood was collected from 30 HIV infected Indians.DNA sequence analysis of the nef and ltr genes was performed.

RESULTS: All samples were confirmed clade C using the V3 loop and nef gene. Alignment with the Los Alamos South African ltr database confirmed the extra NF-kB site. Using the nef gene, all samples clustered closely with the Botswana clade C. Previously documented occassonal amino acid insertions were also found in the nef gene.

CONCLUSIONS: We report the extra NF-kB site in our isolates, the significance of which remains undefined. We also conclude that the nef gene is fairly conserved. These results are compatible with findings already established in South African blacks and Indians in India suggesting interracial transmission of the virus in South Africa.

Keywords: AEGIS, Genes, nef, HIV Infections, Terminal Repeat Sequences, HIV Seropositivity, HIV Long Terminal Repeat, Variation (Genetics), Sequence Analysis, DNA, South Africa, Seroepidemiologic Studies, Botswana, India, pathogenicity, genetics

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C10729