HIV strains in India resist some broadly neutralising antibodies, Pg11

Key Highlights:

• Research indicates that HIV strains in India exhibit resistance to certain broadly neutralising antibodies (bNAbs).
• The study, which compared HIV variants in India and South Africa, revealed that Indian strains are more sensitive to some bNAbs but more resistant to others.
• Researchers have proposed a novel cocktail of three bNAbs (BG18, N6, and PGDM1400) predicted to effectively neutralise a large proportion of circulating Indian HIV-1 strains.
• The study underscores the importance of region-specific HIV prevention strategies, such as passive immunisation and vaccine design, due to the virus's genetic diversity.

Detailed Insights:

• Broadly neutralising antibodies (bNAbs) have shown promise in neutralising a wide range of HIV variants, but HIV's genetic variation poses a significant challenge.
• HIV can be classified into subtypes, with each subtype containing numerous circulating strains that differ in their sensitivity to bNAbs.
• The study found that Indian strains of HIV are most effectively neutralised by bNAbs targeting the V3 glycan region on the viral surface, while antibodies aimed at the V1/V2 apex were less effective.
• Regional differences exist, with Indian strains being more sensitive to antibodies like N6, 10-1074, and BG18 but slightly more resistant to CAP256-VRC26.25 compared to South African strains.
• These differences likely arise from subtle changes in the viral spike protein, particularly in the structural motifs that form the antibody binding sites.
• The research highlights the need for ongoing surveillance of both viral diversity and antibody effectiveness to ensure the most promising antibody combinations are prioritised for clinical development.
• Region-specific studies are essential for designing HIV therapies and vaccines that are truly effective worldwide, considering the virus's ability to evolve differently in different regions.

Key Concepts Involved:

• Broadly Neutralising Antibodies (bNAbs): Protein molecules capable of neutralising a wide range of HIV variants at low concentrations.
• HIV Subtypes: Similar but not identical variants of the HIV virus, each with numerous circulating strains.
• Viral Spike Protein: A structure on the surface of the HIV virus that facilitates entry into host cells and is a target for bNAbs.