Naturally occurring N-acetylglucosamine (GlcNAc) molecules attach to T-cell receptors and these GlcNAc "branches" form a lattice on the cell surface that prevents the receptors from clustering near where the antigens are located, US researchers found, according to the latest issue of New Scientist available here Thursday.

GlcNAc is a similar but more potent compound like glucosamine, a dietary supplement commonly taken by people with osteoarthritis, which has some immunosuppressive effects.

A large number of proteins in the body are modified by the attachment of sugar molecules to their surface through a process called glycosylation, and altered glycosylation has been implicated in some autoimmune diseases triggered when receptors on the outside of immune cells called T-helper 1 (Th1) cells start binding "self" antigens rather than pieces of foreign invaders. And anything that decreases the amount of binding should suppress the autoimmune response.

Researchers under the leadership of Michael Demetriou at the University of California, Irvine, US, found that mice given oral GlcNAc supplements had twice as much GlcNAc branching on their T- cell receptors as untreated mice.

The researchers also found that T-cells engineered to cause the mouse equivalent of MS failed to do so if they had been incubated in GlcNAc first.

A daily oral dose of GlcNAc also prevented type 1 diabetes in mice genetically engineered to develop the disease, the researchers found.

According to the report, an earlier small study of 12 children with autoimmune inflammatory bowel disease, suggested that GlcNAc lessened symptoms in eight of them.

As glucosamine and GlcNAc are immunosuppressive, more research is needed to prove the safety of their supplements in humans with autoimmune disease, researchers said.

Source: Xinhua

http://english.people.com.cn/200706/08/eng20070608_382138.html