|
Particular infection-fighting proteins
act as natural antibiotics in the skin of mice, according
to US scientists. It is the first evidence in mammals that
such proteins, known as antimicrobial peptides, can perform
like antibiotic drugs.
Since humans also have these types of
proteins, the researchers say their findings suggest people
can churn out their own antibiotics in the face of a germ
invasion.
The study looked at the role of cathelicidins
in the innate immune defenses of mice. Cathelicidins, or caths,
are small pieces of protein that dwell in certain cells in
mammals, including humans. While caths have been known to
aid in the body's defenses -- such as helping wound healing
-- it has been unclear whether they can kill infectious bugs.
Investigators studied a mouse cathelicidin
called CRAMP, which has a human counterpart called LL-37.
This suggests that the human cath is also an innate antibiotic.
Caths are located in various tissues
other than skin, including the lungs and intestines, and in
white blood cells called neutrophils.
They jump into action when necessary,
increasing their levels in tissue under assault. Unlike antibiotic
drugs, which are notoriously overused, the body doles out
caths only when needed.
Nature
November 22, 2001;414:454-457
| 