White Blood Cells Are Picky About Sugar

[Guest guest]

White Blood Cells Are Picky About Sugar

Newswise

http://www.newswise.com/articles/view/531350/

Description

Neutrophils recognize and respond to a particular form of sugar

contained on the surface of pathogenic fungi. The key sugar could be

used to boost the immune system and fight microbial infections that

are resistant to current treatments.

Newswise — Biology textbooks are blunt—neutrophils are mindless

killers. These white blood cells patrol the body and guard against

infection by bacteria and fungi, identifying and destroying any

invaders that cross their path. But new evidence, which may lead to

better drugs to fight deadly pathogens, indicates that neutrophils

might actually distinguish among their targets.

A scientist in the lab of Whitehead Member Gerald Fink has

discovered that neutrophils recognize and respond to a specific form

of sugar called beta-1,6-glucan on the surface of fungi. This sugar

comprises just a small fraction of the fungal cell wall, much less

than another sugar with a slightly different chemical conformation

called beta-1,3-glucan. Because the scarce form of the sugar elicits

a much stronger reaction from immune cells than the abundant one, it

appears that neutrophils can distinguish between two nearly

identical chemicals.

" These results show that engulfment and killing by neutrophils

varies, depending on cell wall properties of the microbe, " explains

Whitehead postdoctoral researcher Ifat Rubin-Bejerano, first author

on the paper, which appears July 11 in the journal Cell Host &

Microbe. " We showed that neutrophils respond in a completely

different way to slight changes in sugar composition. If we are able

to use this unique sugar to excite the immune system, it may help

the human body fight infection. "

" Previously, everyone thought that these key cells of the immune

system weren't picky and would eat anything that looked foreign, "

adds Fink, who is also an MIT professor of biology. " Ifat's work has

shown that the cells aren't little Pac-Men, but can discriminate one

pathogen from another. "

Rubin-Bejerano had evidence that neutrophils respond to beta-glucan.

After coating tiny beads with a variety of substances (including

beta-1,3-glucan and beta-1,6-glucan), she exposed them to the

neutrophils and was surprised to see a striking difference in their

response to the two sugars. The neutrophils quickly engulfed many of

the beads coated with beta-1,6-glucan, but only a few of those

covered in beta-1,3-glucan.

Previous studies indicated that blood serum (basically blood minus

cells) helps neutrophils recognize their enemies, so Rubin-Bejerano

decided to look for clues to their response in this mixture. She

identified several proteins in serum that bind to beta-1,6-glucan,

but not beta-1,3-glucan, and then pinpointed a molecule on the

surface of the neutrophil that recognizes these proteins.

To link her experiments back to real fungi, Rubin-Bejerano worked

with the pathogen Candida albicans, which is the most common fungus

in blood stream infections. She used an enzyme to digest beta-1,6-

glucan from the fungal cell wall, leaving the beta-1,3-glucan

intact. She then unleashed the neutrophils on these altered cells

and observed a 50 percent reduction in the immune response.

Our bodies maintain a fine balance between the immune system and

microbes. Antibiotics and antifungals tilt the balance in favor of

the immune system by targeting the microbes directly. A substance

like beta-1,6-glucan could help tilt this balance further by

stimulating immune cells.

Rubin-Bejerano's work offers hope for combating the growing problem

of microbial infections, which can seriously threaten human health—

particularly in patients with compromised immune systems. In fact,

Rubin-Bejerano co-founded a company called ImmuneXcite to explore

this possibility.

[Guest guest]

interesting, very interesting.

--- In , " tigerpaw2c " <tigerpaw2c@...>

wrote:

>

> White Blood Cells Are Picky About Sugar

> Newswise

>

> http://www.newswise.com/articles/view/531350/

> Description

>

> Neutrophils recognize and respond to a particular form of sugar

> contained on the surface of pathogenic fungi. The key sugar could

be

> used to boost the immune system and fight microbial infections that

> are resistant to current treatments.

>

[Guest guest]

WHAT'S STRANGE IS THAT DURING MY EXPOSYRE, MY APPETITE WAS GONE AND

HEALTHY FOODS WERE REPLUSIVE TO ME, I HAD TO FORCE MYSELF TO EAT

ANYTHING AND MY STOMACH WOULD GROWL AND RUMMBLE WHEN I DID AND DISPOSE

OF IT QUICKLY. BUT MY GRAVEING FOR SUGAR WAS OVERBOARD. THIS WAS DURING

EXPOSURE IN FIRST HOME, BEFORE TOXIN OVERLOAD IN SECOND HOME WHICH

BROUGHT ON FOOD ALLERGIES.

> >

> > White Blood Cells Are Picky About Sugar

> > Newswise

> >

> > http://www.newswise.com/articles/view/531350/

> > Description

> >

> > Neutrophils recognize and respond to a particular form of sugar

> > contained on the surface of pathogenic fungi. The key sugar could

> be

> > used to boost the immune system and fight microbial infections that

> > are resistant to current treatments.

> >

>