Molecule of the Month: Broadly Neutralizing Antibodies
Structural studies of broadly neutralizing antibodies are paving the way to vaccines for HIV, influenza and RSV
The Immune System Fights Back
Exploring the Structure
RSV Vaccine Design (PDB entries 4jhw and 4mmv)
The ultimate goal of this research is to find way to make vaccines that will spur production of these broadly neutralizing antibodies, to provide protection against infection. Remarkably, this goal of structure-based vaccine design has been achieved for respiratory syncytial virus (RSV). The work started with a structure of a particularly potent antibody that neutralizes the receptor-binding site of the viral fusion glycoprotein, shown here on the left (PDB entry 4jhw ). Based on this structure, researchers engineered a soluble form of the glycoprotein that adopts the same shape as the antibody-bound form, requiring a number of mutations, shown here on the right (PDB entry 4mmv ). When mice and macaques are vaccinated with this engineered protein, it provides immunity from the virus. To explore these proteins in more detail, click on the image for an interactive Jmol.
Topics for Further Discussion
- PDB entry 1op5 includes an unusual domain-swapped antibody, which creates a third binding site in addition to the two conventional binding sites on the two Fab domains. It is a broadly neutralizing antibody that attacks the sugars on the surface of HIV envelope glycoprotein.
- Because they are so flexible, crystallographers typically study a fragment of antibodies which includes only one of the Fab arms. To see the structure of some intact antibodies, look at the examples in the Molecule of the Month on antibodies.
February 2014, David Goodsellhttp://doi.org/10.2210/rcsb_pdb/mom_2014_2