AEGiS-11IAC: Envelope sequences and biological characterization of HIV-1 subtype E isolates from Thailand.

11th International AIDS Conference

Vancouver, British Columbia — July 7-12, 1996

Envelope sequences and biological characterization of HIV-1 subtype E isolates from Thailand.

Int Conf AIDS 1996 Jul 7-12; 11:216 (abstract no. Tu.A.104)
Auewarakul P, McLane MF, Wasi C, Essex M; Harvard School of Public Health, Boston, MA, USA. Fax: 617-739-8348. E-mail: pauewara@hsph.harvard.edu.

OBJECTIVE: To obtain HIV-1 subtype E isolates from heterosexually infected individuals in Thailand and to analyze their envelope sequences and biological properties.

METHODS: HIV-1 were isolated by co-cultivation of peripheral blood mononuclear cell (PBMC) from infected pregnant women with donor PBMC. The infected individuals had no history of intravenous drug use or blood transfusion. DNAs were prepared from the cultured PBMC, and nested PCR were performed to obtain 2.8 kb fragment covering the whole gp160 envelope gene. The fragments were cloned into PCR II vector and sequenced. Growth kinetics in PBMC, syncytium induction in MT-2 cell, and neutralization or enhancing activity of the isolates by homologous plasma were studied.

RESULTS: Four HIV-1 subtype E isolates and their complete envelope sequences were analyzed. Of these, two isolates grew to high titer in PBMC (#406, 449), one of which induced syncytia in MT-2 (#449). Infectivity of this isolate in PBMC was enhanced, whereas that of the other three were neutralized by homologous plasma. The three isolates (#401, 406, 418) with non-syncytia inducing (NSI) phenotype had GPGQ amino acid sequence at the tip of V3 loop, whereas the one with syncytia inducing (SI) phenotype had GPGR. The isolates that grew only to low titer in PBMC (#401, 418) carried an extra N-linked glycosylation site in the V3 loop. The V3 loop of the isolates with high titer growth (#406, 449) showed high net positive charge. Two isolates (#406, 418) carried an extra disulfide bridge in V4. The envelopes are being subcloned into a HXB2 background to confirm the phenotype of the clones.

CONCLUSION: GPGR motif, lack of extra N-linked glycosylation site and net positive charge in V3 loop correlated with high titer growth and SI phenotype in the subtype E envelope clones analyzed.

Keywords: AEGIS, HIV-1, Giant Cells, Phenotype, Thailand, Pregnancy, Female, Human, genetics, ICA11

960707
TuA104