AEGiS-11IAC: Genetic diversity of HIV-1 in Thailand, 1994-95.

11th International AIDS Conference


Vancouver, British Columbia — July 7-12, 1996

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Genetic diversity of HIV-1 in Thailand, 1994-95.

Int Conf AIDS 1996 Jul 7-12; 11:225 (abstract no. Tu.A.375)
Subbarao S, Limpakarnjanarat K, Bhumisawasdi J, Young NL, Kalish ML, Schochetman G, Mastro TD; CDC, Atlanta, GA, USA. Fax: (404)639-2660. E-mail: sfs2@ciddas1.em.cdc.gov.

OBJECTIVE: To determine the genetic heterogeneity of HIV-1 strains in Thailand using a larger sample with greater geographic diversity than in previous molecular epidemiologic studies.

METHODS: A convenience sample was made of 215 asymptomatic HIV+persons consisting of 64 injecting drug users [IDU] and 151 with sexual risk. Viral subtypes were determined by a combination of peptide-binding immunoassay (PEIA) and hybridizations of nested PCR fragments of the env gene (C2-V5) with subtypes E and B' (Thai subtype B variant)-specific oligonucleotide probes. The C2-V4 region was sequenced for 97 samples.

RESULTS: Overall, 175 (81%) strains were subtype E (including 97%[147 of 151] from non-IDU) and 37 (17%) were subtype B'. Only two strains were determined to be "typical" North American-like subtype B viruses and the subtype for one strain has not yet been determined. Among IDUs, subtype B' and E strains accounted for 55% and 44% of the infections, respectively. The average intra-subtype genetic distance in a representative set of 20 subtype E and 17 B' sequences was 6.3% and 3.4%, respectively. While GPGQA was the most common V3 loop crown motif among subtype B' viruses, 33% displayed the GPGRA motif more common among North American subtype B strains. Among subtype E sequences, 92% had GPGQV at the crown of the V3 loop; 9 of 11 E strains that could not be subtyped by PEIA displayed atypical amino acid sequences at this location. The DNA probes were 100% sensitive and specific for subtypes E and B' including 16 of 215 strains that were either dually reactive or non-reactive by PEIA. Monoreactive PEIAs were 99% specific for subtypes E and B'.

CONCLUSIONS: Sequence analysis of a wide sample generates data that can be used to modify peptides for PEIAs, design candidate HIV-1 vaccines, and plan vaccine efficacy trials. The mix of B' and E among Thai IDUs offers opportunities to study phenotypic differences among HIV-1 subtypes.

Keywords: AEGIS, HIV-1, Genes, env, Variation (Genetics), AIDS Vaccines, Polymerase Chain Reaction, DNA Primers, Thailand, Peptides, Epidemiologic Studies, genetics, ICA11KWDaegis,hiv-1,genes,env,variation(genetics),aidsvaccines,polymerasechainreaction,dnaprimers,thailand,peptides,epidemiologicstudies,genetics,ica11

960707
TuA375

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