快猫短视频

ANTIBODIES turn out to have a talent for destruction they鈥檝e managed to keep
well hidden till now. They may play a much more active role in
preventing鈥攁nd causing鈥攄isease than previously thought.

Antibodies have always been seen as scouts rather than soldiers.
Immunologists believe they latch onto foreign cells, viruses or
proteins, but rely on other parts of the immune system such as white blood cells
to finish them off.

But while Paul Wentworth, Kim Janda and their colleagues at the Scripps
Research Institute in La Jolla, California, were studying an antibody, they
found that it could produce hydrogen peroxide, which can destroy cells and
viruses. They then checked 39 other antibodies, including ones from mice, rats,
hamsters, rabbits, sheep, goats, horses and humans. Every one could produce
hydrogen peroxide. 鈥淲e certainly didn鈥檛 expect antibodies to have this amazing
ability,鈥� says Wentworth.

Further tests showed that the antibodies convert a form of dissolved oxygen
known as singlet molecular oxygen into a highly reactive type that spontaneously
forms hydrogen peroxide. Intriguingly, singlet molecular oxygen is also created
as an inactive by-product when white blood cells attack invading microbes with a
spray of hydrogen peroxide and other related chemicals.

This suggests that antibodies might add extra punch to these attacks by
鈥渞ecycling鈥� the oxygen back into hydrogen peroxide. But this also means that
antibodies could exacerbate the problems caused by immune cell overactivity,
such as autoimmune diseases.

鈥淚t is a startling observation,鈥� says Donald Landry of Columbia University in
New York, who studies antibodies. He says this unexpected dual role for
antibodies shows how well evolution has tuned the immune system. 鈥淣ature does
not leave many opportunities unplumbed.鈥�