AEGiS-12IAC: Serologic and phylogenetic characterization of HIV-1 subtypes in Cameroon.

12th International AIDS Conference

Geneva, Switzerland - June 28-July 3, 1998

Serologic and phylogenetic characterization of HIV-1 subtypes in Cameroon.

Int Conf AIDS 1998 Jun 28-Jul 3; 12:20 (abstract no. 11189)

Brennan C, Hackett J, Vallari A, Zekeng L, Gurtler L, Kaptue L, Devare SG
Abbott Laboratories, North Chicago IL 60064, USA.

OBJECTIVES: To determine the HIV genetic subtypes present in Cameroon and to evaluate viral sequence variation.

METHODS: Plasma was collected from asymptomatic blood donors in Yaounde and Douala, Cameroon and screened for HIV infection using a variety of serologic assays. Total nucleic acid was extracted from the seropositive plasma samples and subjected to RT-PCR for amplification of the env gp41 immunodominant region (IDR, 438 bp), a region of gag p24 (483 bp), and pol p32 (898 bp). The PCR fragments were sequenced directly using an automated sequencer. Genetic subtype was determined by phylogenetic analysis of the viral sequences.

RESULTS: Based on initial field testing, 103 HIV seropositive plasma units were collected. Confirmatory testing was performed on these samples using several commercial EIAs, research EIAs, and Western blots. Serology reactivity indicated that the samples included 1 HIV-1 group O infection, 1 HIV-2 infection, and 101 HIV-1 group M infections. The HIV-2 sample was PCR negative. All the HIV-1 seropositive samples were PCR positive. Phylogenetic analysis of the sequences confirm the presence of 1 group O and 101 group M infections. The results of subtype analysis of the group M sequences are: 85 (83%) subtype A/A (IDR/gag), 1 B/B, 1 D/D, 3 (3%) F/F, 5 (5%) G/G, 1 A/F, and 5 (5%) G/A. The env gp 120 C2V3 region was amplified from 7 of the 9 non-A subtype samples; all, but one, have the amino acid sequence GPGQ at the tip of the V3 loop.

CONCLUSIONS: While HIV-1 subtype A predominates the HIV epidemic in Cameroon, many subtypes of group M, as well as group Q and HIV-2, are present in the population. At least 6% of the infections have a heterogeneous subtype (due to mixed infection or recombinant viruses) reflecting the growing complexity of the HIV epidemic when multiple subtypes are present in the population.

Keywords: AEGIS, HIV-1, HIV-2, HIV Envelope Protein gp41, HIV Core Protein p24, HIV Seropositivity, HIV Infections, HIV Envelope Protein gp120, HIV Antibodies, HIV, Variation (Genetics), HIV Integrase, Blood Donors, Polymerase Chain Reaction, Amino Acid Sequence, Cameroon, immunology, genetics, ICA12
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