title: Phenotypic and genotypic characteristics of human immunodeficiency virus type 1 from patients with AIDS in northern Thailand.
abstract: Primary human immunodeficiency virus type 1 (HIV-1) isolates were obtained from 22 patients with AIDS from northern Thailand, where HIV-1 is transmitted primarily through the heterosexual route. Viral sequences were determined for the 22 patients with AIDS, and all were subtype E HIV-1 on the basis of sequence analysis of a region from the envelope protein gp120. Syncytium-inducing (SI) viruses were detected for 16 of 22 patients with AIDS by using MT-2 cells. Characteristics of amino acid sequences in V3 which have not been reported previously for subtype B SI HIV-1 were associated with the subtype E HIV-1 SI phenotype. The SI viruses from our study population contain predominantly a GPGR or GPGH motif at the tip of the V3 loop, in contrast to the previously described subtype E HIV-1 from Thailand which contained predominantly GPGQ. All the SI viruses lost a potential N-linked glycosylation site in V3 which is highly conserved among previously described subtype E HIV-1 isolates from asymptomatic patients from Thailand. HIV-1 envelope sequences including V3 from some patients with AIDS were significantly more divergent than viruses from asymptomatic patients in Thailand characterized 2 years ago or earlier. These results suggest that emergence of subtype E SI HIV-1 variants is associated with the development of AIDS, as it is for subtype B HIV-1. The divergence of subtype E HIV-1 in patients with AIDS as the disease progresses, and the divergence of subtype E HIV-1 in the infected population as the epidemic continues in Thailand, may have important implications for vaccine development.
authors.affiliation: Department of Molecular Microbiology and Immunology, Johns Hopkins University School of Hygiene and Public Health, Baltimore, Maryland 21205, USA.
authors.forename: X F
authors.initials: XF
authors.lastname: Yu
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: C
authors.initials: C
authors.lastname: Beyrer
authors.forename: D D
authors.initials: DD
authors.lastname: Celentano
authors.forename: C
authors.initials: C
authors.lastname: Khamboonruang
authors.forename: E
authors.initials: E
authors.lastname: Allen
authors.forename: K
authors.initials: K
authors.lastname: Nelson
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology / Q000821:virology*; D000595:Amino Acid Sequence; D005838:Genotype; D015497:HIV-1 / Q000145:classification / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D013785:Thailand / Q000453:epidemiology