HIV-1 subtype C in vitro growth and coreceptor utilization.

Area of Science:

• Virology
• Immunology
• Epidemiology

Background:

• Human immunodeficiency virus type 1 subtype C (HIV-1C) is the most prevalent globally, causing approximately 50% of infections.
• Southern Africa bears a significant burden of HIV-1C, necessitating research into its unique biological characteristics.
• Understanding HIV-1C tropism is crucial for developing effective interventions.

Purpose of the Study:

• To investigate the chemokine receptor usage of HIV-1C isolates from Botswana.
• To determine the predominant coreceptor tropism of HIV-1C in this region.
• To assess potential evolution of HIV-1C tropism over the course of infection.

Main Methods:

• Generation of HIV-1C virus isolates from infected individuals at various disease stages.
• Analysis of coreceptor tropism, specifically chemokine receptor usage (CCR5 and CXCR4).
• Phenotypic characterization of virus entry based on coreceptor utilization.

Main Results:

• The R5 tropism (CCR5-using) was predominant among the studied HIV-1C isolates.
• A smaller proportion of viruses exhibited dualtropic X4R5 (CCR5 and CXCR4-using) tropism.
• No viruses with pure X4 tropism (CXCR4-only using) were identified, indicating a lack of evolution towards this phenotype.

Conclusions:

• HIV-1C in Botswana primarily utilizes R5 and X4R5 coreceptors for entry.
• The absence of X4-only tropism suggests limited viral evolution towards this entry pathway in the aging epidemic.
• These findings have significant implications for the design and efficacy testing of antiretroviral therapies and prevention strategies.