Sugary bugs subvert antibodies

August 11, 2014
Sugary bugs subvert antibodies
Researchers show how the body's antibody response can protect—not destroy—the bacterium Pseudomonas aeruginosa (pictured). Credit: ©Kierbel, A., et al. 2007. J. Cell Biol. doi:10.1083/jcb.200605142

A lung-damaging bacterium turns the body's antibody response in its favor, according to a study published in The Journal of Experimental Medicine.

Pathogenic bacteria are normally destroyed by antibodies, that coat the outer surface of the bug, laying a foundation for the deposition of pore-forming "complement" proteins that poke lethal holes in the . But despite having plenty of antibodies and complement proteins in their bloodstream, some people can't fight off infections with the respiratory bacterium Pseudomonas aeruginosa. And chronic infection can lead to a condition called bronchiectasis, characterized by persistent cough, shortness of breath, and chest pain.

A group of researchers at the University of Birmingham, England, now find that the antibody response to Pseudomonas can get in its own way. In a subset of infected bronchiectasis patients with particularly poor lung function, they noticed an abundance of one specific type of antibody, called IgG2, which stripped the blood of its normal bug-killing capacity. The IgG2 proteins bound to extra-long sugars on the , a feature unique to the bugs infecting these patients. When these sugar-specific antibodies were removed, the blood's antibacterial prowess was restored.

Exactly how these IgG2 molecules protect the bug is unclear, but they may lure away from more vulnerable parts of the bacterial surface. The discovery of antibodies that protect the bug instead of the person may help to explain why two vaccines based on these extra-long sugars resulted in worse disease in immunized individuals.

Explore further: (Antibody) orientation matters

More information: Wells, T.J., et al. 2014. J. Exp. Med. DOI: 10.1084/jem.20132444

Related Stories

(Antibody) orientation matters

December 10, 2012

The orientation of antibody binding to bacteria can mean life or death to the bug, according to a study published in The Journal of Experimental Medicine on December 10th. These findings may help explain why these bacteria ...

Improving human immunity to malaria

August 1, 2012

The deadliest form of malaria is caused the protozoan Plasmodium falciparum. During its life-cycle in human blood, the parasite P. falciparum expresses unique proteins on the surface on infected blood cells.

Recommended for you

Artificial beta cells

December 8, 2016

Researchers led by ETH Professor Martin Fussenegger at the Department of Biosystems Science and Engineering (D-BSSE) in Basel have produced artificial beta cells using a straightforward engineering approach.

Key regulator of bone development identified

December 8, 2016

Loss of a key protein leads to defects in skeletal development including reduced bone density and a shortening of the fingers and toes—a condition known as brachydactyly. The discovery was made by researchers at Penn State ...

Researchers question lifelong immunity to toxoplasmosis

December 8, 2016

Medical students are taught that once infected with Toxoplasma gondii—the "cat parasite"—then you're protected from reinfection for the rest of your life. This dogma should be questioned, argue researchers in an Opinion ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.