Related Experiment Videos
Epitope exposure on functional, oligomeric HIV-1 gp41 molecules
Q J Sattentau1, S Zolla-Pazner, P Poignard
1Centre d'Immunologie de Marseille-Luminy, France.
Virology
|January 10, 1995
Summary
Monoclonal antibodies binding to HIV-1 gp41 were studied. Soluble CD4 treatment revealed gp41 epitopes masked by gp120, but reduced binding to a neutralization epitope.
Area of Science:
- Immunology
- Virology
- Structural Biology
Background:
- The HIV-1 envelope glycoprotein complex consists of gp120 and gp41.
- Understanding the structure and accessibility of gp41 epitopes is crucial for vaccine and therapeutic development.
Purpose of the Study:
- To investigate the binding of monoclonal antibodies (mAbs) to various epitopes on the HIV-1 gp41 transmembrane glycoprotein.
- To determine the effect of soluble CD4 (sCD4) on the accessibility of gp41 epitopes.
Main Methods:
- Utilized HIV-1 infected cells (HX10 molecular clone) for antibody binding assays.
- Compared antibody binding at different temperatures (4°C and 37°C) and in the presence/absence of sCD4.
Main Results:
- Gp41 mAb binding increased at 37°C compared to 4°C.
- sCD4 treatment enhanced binding to gp41 epitopes (residues 521-663), suggesting gp120 masking.
- sCD4 reduced binding to a neutralization epitope (residues 662-667).
- Antibodies to residues 725-750 showed similar binding to infected and non-infected cells, unaffected by sCD4, indicating potential cytoplasmic localization.
Conclusions:
- The gp120 subunit masks certain gp41 epitopes, which become accessible upon sCD4 binding and gp120 dissociation.
- A neutralization epitope on gp41 is sensitive to sCD4 binding.
- An epitope in the 725-750 region is likely not externally exposed on the cell surface.