Unmasking anthrax for immune destruction

Apr 30, 2010
Overexpression of CapD results in a smaller capsule in Bacillus anthracis. Capsule is indicated as the clear area around the bacillus. Wild-type strain is shown on the left and the strain over-expressing CapD is shown on the right. Credit: Arthur Friedlander

Anthrax-causing bacteria can be engineered to shed their invisibility cloaks, making it easier for the immune system to eradicate it, according to a new study published in Microbiology. The work could lead to new measures to treat anthrax infection in the event of a biological warfare attack.

is a particularly lethal pathogen because it manages to escape recognition by the host's immune system by coating itself with a protective capsule around its surface. A key called capsule depolymerase (CapD) anchors the capsule to the cell surface. CapD can also cut and release some of the capsule into small fragments that are thought to interfere with specific parts of the immune system, offering further protection to the .

Scientists at the U.S. Army Medical Research Institute of Infectious Diseases discovered that by engineering B. anthracis to produce higher-than-normal amounts of CapD, the protective capsule is chopped up and released as tiny fragments. The bacterium is left nearly completely unmasked and therefore vulnerable to immediate detection and destruction by the macrophage and neutrophil cells of the immune system. "By engineering B. anthracis to over-produce CapD, we are effectively turning the bacterium's own weapon on itself," explained Dr. Arthur Friedlander, one of the principal investigators in the study.

B. anthracis is the most commonly mentioned pathogen associated with biological warfare. This bacterium can form resilient spores that survive dormant in the environment for long periods of time. When these spores are aerosolised the bacterium can be very effectively distributed. After human inhalation the spores reactivate and cause severe infection that is usually fatal if left untreated.

Dr Friedlander believes his groups' findings could have significant clinical impact. "Many , including B. anthracis, produce a capsule surrounding them that prevents the infected host from killing them, improving their chances of causing disease," he explained. "Understanding the mechanisms of virulence used by the anthrax bacterium is vital to developing medical countermeasures against it in the event of a biological attack."

Finding a way to encourage B. anthracis to unwittingly unmask itself, using the bacterium's own machinery would be a novel approach to eradicating the pathogen. "What is more, these measures may also be effective against strains of B. anthracis that have been genetically engineered to be resistant to antibiotics and/or existing vaccines," suggested Dr. Friedlander.

Explore further: The malaria pathogen's cellular skeleton under a super-microscope

More information: doi:10.1099/mic.0.035857-0

Provided by Society for General Microbiology

5 /5 (2 votes)

Related Stories

Researchers image crucial anthrax protein

Jul 14, 2009

(PhysOrg.com) -- Anthrax, long feared for its potential as a biological weapon, has lost some of its mystery. Researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory, in collaboration ...

Researchers pave the way for anthrax spore standards

Apr 15, 2008

Researchers from the National Institute of Standards and Technology (NIST) and the U.S. Army Dugway (Utah) Proving Ground have developed reliable methods based on DNA analysis to assess the concentration and ...

Anthrax cellular entry point uncovered

Jan 25, 2008

The long-sought-after biological “gateway” that anthrax uses to enter healthy cells has been uncovered by microbiologists at the University of Alabama at Birmingham (UAB).

Anthrax Detector Developed

Aug 16, 2006

Spores of the dreaded Bacillus anthracis have already been used as a bioweapon against the civilian population. Once inhaled, the anthrax pathogen almost always leads to death if the victims are not treated within 24 to 48 ...

Recommended for you

Researchers successfully clone adult human stem cells

11 hours ago

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Researchers develop new model of cellular movement

14 hours ago

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

For resetting circadian rhythms, neural cooperation is key

Apr 17, 2014

Fruit flies are pretty predictable when it comes to scheduling their days, with peaks of activity at dawn and dusk and rest times in between. Now, researchers reporting in the Cell Press journal Cell Reports on April 17th h ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Plants with dormant seeds give rise to more species

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Impact glass stores biodata for millions of years

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...