Neutralizing Antibodies Targeting HIV-1 gp41.

Area of Science:

• Immunology
• Virology
• Structural Biology

Background:

• Discovery of broadly neutralizing antibodies (bnAbs) has advanced HIV-1 vaccine research.
• High-resolution structures of HIV-1 envelope glycoprotein (Env) in complex with bnAbs are now available.
• Focus is on gp41 regions: heptad repeat 1 (HR1), fusion peptide (FP), and membrane-proximal external region (MPER).

Purpose of the Study:

• To summarize structural and functional data of neutralizing antibodies targeting gp41 HR1, FP, and MPER.
• To review antibody access to Env and complex formation with gp41 regions.
• To discuss MPER bnAb binding to lipids and the role of somatic mutations for vaccination strategies.

Main Methods:

• Structural analysis of Env-bnAb complexes.
• Functional assays for antibody neutralization.
• Review of existing literature on gp41, FP, and MPER targeting bnAbs.

Main Results:

• Broadest neutralizing antibodies target the MPER region of gp41.
• gp41 HR1 and MPER accessibility depend on receptor-induced conformational changes.
• MPER bnAbs may recognize a bipartite epitope including lipids, influenced by somatic mutations.

Conclusions:

• Understanding bnAb targeting of gp41 HR1, FP, and MPER is crucial for HIV-1 vaccine design.
• MPER bnAb characteristics, including lipid binding and epitope recognition, offer insights for vaccination.
• Addressing challenges like gp41 HR1 access and MPER bnAb polyreactivity is vital for effective HIV-1 vaccines.