Antibodies Produce Ozone During Bacterial Killing and Inflammation
By Jason Socrates Bardi
The Scripps Research Institute (TSRI) President Richard A. Lerner, Associate
Professor Paul Wentworth, Jr., Ph.D., and a team of investigators at TSRI
is reporting that antibodies can destroy bacteria, playing a hitherto
unknown role in immune protection. Furthermore, the team found that when
antibodies do this, they appear to produce the reactive gas ozone.
"[Ozone] has never been considered a part of biology before," says Lerner,
who is Lita Annenberg Hazen Professor of Immunochemistry and holds the
Cecil H. and Ida M. Green Chair in Chemistry. The report will appear in
an upcoming issue of the journal Science.
The ozone may be part of a previously unrecognized killing mechanism
that would enhance the defensive role of antibodies by allowing them to
subject pathogens to hydrogen peroxide and participate directly in their
killing. Previously, antibodies were believed only to signal an immune
This ability of antibodies to generate toxic compounds may also link
them to a number of inflammatory diseases, such as atherosclerosis, lupus,
multiple sclerosis, and rheumatoid arthritis. Furthermore, this research
opens up exciting possibilities for new antibody-mediated therapies for
conditions ranging from bacterial and viral infection to cancer.
Recognition and Killing in the Same Molecule
Also called immunoglobulins, antibodies are secreted proteins produced
by immune cells that are designed to recognize a wide range of foreign
pathogens. After a bacterium, virus, or other pathogen enters the bloodstream,
antibodies target antigensproteins, fat molecules, and other pieces
of the pathogenspecific to that foreign invader. These antibodies
then alert the immune system to the presence of the invaders and attract
lethal "effector" immune cells to the site of infection.
For the last hundred years, immunologists have firmly held that the
role of antibodies was solely to recognize pathogens and signal the immune
system to make an immune response. The conventional wisdom was that the
dirty work of killing the pathogens was to be left to other parts of the
Now, Lerner, Wentworth, and their colleagues have demonstrated that
antibodies also have the ability to kill bacteria. This suggests that
rather than simply recognizing foreign antigens and then activating other
parts of the immune system to the site of infection, the antibodies may
further enhance the immune response by directly killing some of the bacteria
Antibodies do this by producing the chemical oxidant hydrogen peroxidebest
known as the foamy formulation used for first-aid. Hydrogen peroxide is
lethal to bacterial cells because it pokes holes in their cell walls,
bursting the cells and killing them.
In the Science paper, the TSRI team reports the effective killing of
E. coli bacteria through hydrogen peroxide production by antibodies specific
for that bacteria.
The Ozone Hole in Each One of Us
Certainly the most surprising result that Lerner, Wentworth, and their
colleagues found was that antibodies appear to make ozone, which they
detected through its chemical signature. They have not yet demonstrated
conclusively that what they found is ozone, but they are highly confident
that ozone is what the antibodies are producing because no other known
molecule has the same chemical signature.
Ozone is a particularly reactive form of oxygen that exists naturally
as a trace gas in the atmosphere, constituting on the average fewer than
one part per million air molecules. But it is noted mainly where its presence
or absence poses a threat to public health.
The gas is perhaps better known for its crucial role absorbing ultraviolet
radiation in the upper reaches of earth's stratosphereabout 25 km
above the surfacewhere it is concentrated in a so-called ozone layer,
protecting life on earth from damaging solar radiation.
Ozone is also a familiar component of air in industrial and urban settings
where the highly reactive gas is a hazardous component of smog in the
summer months. Never before has ozone been detected in biology.
"All our analytical data point to this oxidant possessing the chemical
signature of ozone," says Wentworth, "in which case, this is a new molecule
in biology and therefore may have tremendous ramifications for signaling
Proof for a Proposed Reaction Pathway
All antibodies have the ability to produce hydrogen peroxide, the report
adds, but they need to first have available a molecule known as "singlet"
oxygenanother highly reactive oxygen speciesto use as a substrate.
Singlet oxygen is an electronically excited form of oxygen that forms
spontaneously during normal metabolic processes or when oxygen is subjected
to visible or ultraviolet light in the presence of a sensitizer. "Phagocytic"
innate immune cells, like neutrophils, also produce singlet oxygen and
are the most likely source of the substrate for antibodies, since during
an immune response, antibodies will recruit neutrophils and other immune
cells to the site of an infection.
Once there, the neutrophils will engulf and destroy bacteria and other
pathogens by blasting them with singlet oxygen and other oxidative molecules.
The antibodies reduce singlet oxygen by combining it with water to produce
hydrogen peroxide, producing ozone as a side product.
Interestingly, all antibodies have the ability to do this, which leads
the TSRI team to speculate that the removal of singlet oxygen may have
been the original role of antibodies. In a previous report, the same team
speculated an ancient form of antibodies may have existedmolecules
whose role was to catalyze singlet oxygen destruction, since singlet oxygen
can potentially destroy any cell, making it dangerous to have around.
Prior to the evolution of the modern antibody-mediated humoral immune
response in vertebrates hundreds of millions of years ago, ancient antibodies
may have been responsible for controlling the release of highly reactive
and potentially dangerous singlet oxygen. Later, when antibodies developed
as part of the adaptive arm of the immune system, they kept their original
function because it provided a bit of extra lethality.
Another interesting finding is that the antibodies carry the reaction
through an unusual intermediate. Lerner, Wentworth, and their colleagues
postulate that the antibodies carry the reaction through an intermediate
chemical species of dihydrogen trioxide, a reduced form of ozone.
Dihydrogen trioxide has also never before been observed in biological
systems, and its presence as an intermediate has been the source of considerable
speculation in the scientific community.
The team's reported detection of ozone is strong support of this proposed
dihydrogen trioxide intermediate, and now the team is tackling the larger
question of what it means.
"This is a novel set of observations and very interesting onesthere
are a million questions [we could ask]," says TSRI Professor Bernard Babior,
"What does the ozone do to the body's proteins, nucleic acids? Are there
lethal concentrations of ozone? Does it have anything to do with other
reactive species in the body?"
The research article, "Evidence for Antibody-Catalyzed Ozone Formation
in Bacterial Killing and Inflammation" is authored by Paul Wentworth,
Jr., Jonathan E. McDunn, Anita D. Wentworth, Cindy Takeuchi, Jorge Nieva,
Teresa Jones, Cristina Bautista, Julie M. Ruedi, Abel Gutierrez, Kim D.
Janda, Bernard M. Babior, Albert Eschenmoser, and Richard A. Lerner, and
appears in the November 18, 2002 "Science Express," the advanced publication
edition of the journal Science. The article will appear in Science
later this year.
The research was funded by the National Institutes of Health, The Skaggs
Institute for Chemical Biology, and an A.R.C.S. fellowship.
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