Navigation Links
Single Sugar Enables Antibody to Treat Inflammation

For years, researchers have struggled to understand how IVIG worked. Its ability to treat autoimmune diseases seemed to be an apparent contradiction.//

Intravenous immunoglobulin (IVIG) is a complex mixture of IgG antibodies made from human plasma that contains the pooled antibodies from thousands of people, and is only FDA-approved to treat a few assorted conditions; nonetheless, practitioners have used it off-label with varied success in patients with lupus, arthritis and asthma, among other autoimmune disorders. In the body, the antibodies in plasma act as part of the immune response to identify and deactivate foreign invaders. When they begin attacking the body's own cells, the same protective immunoglobulins (known as IgG antibodies) can cause autoimmune disorders like lupus, arthritis and asthma. And yet, when IVIG is infused into people with those exact autoimmune conditions, it calms inflammation rather than causes it.

Jeffery Ravetch, Theresa and Eugene M. Lang Professor and head of Rockefeller's Leonard Wagner Laboratory of Molecular Genetics and Immunology, was struck by this inconsistency. "If IgG triggers autoimmune disease, how could it be pathogenic and therapeutic?" he asked. "We call it the IgG paradox." Six years ago he started an investigation into exactly how IVIG worked, and what he's discovered could one day lead to a whole new class of therapeutics. In a paper published in the August 4 issue of the journal Science, Ravetch and his colleagues, Falk Nimmerjahn and Yoshi Kaneko, explain what makes IVIG effective: A small fraction of the IgG antibodies in the IVIG solution carry a sugar called sialic acid that is required for its protective ability.

IgG antibodies bind to and activate specific immune cells, with different forms or "subclasses" binding to specific receptors (called Fc receptors) on the immune cell's surface. Antibody subclasses have different abilities to induce inflammation in the body by virt ue of their selective ability to engage either activating or inhibitory Fc receptors. Earlier work had shown that IVIG infusion changed this ratio of activating and inhibitory receptors on the cells that trigger inflammation, rendering the pro-inflammatory autoantibodies in autoimmune diseases, like lupus and arthritis, less inflammatory. The next logical step then, Ravetch says, was determining how the IgG molecules in IVIG preparation could have an anti-inflammatory effect.

Because a therapeutic, anti-inflammatory response to IVIG requires a concentration of IgG antibodies that's hundreds of times greater than is normally used for antibody therapy for cancer or infection, for example, Ravetch and his colleagues began to look for something that was only present in IVIG in small amounts. That's how they discovered that just the very terminal sialic acid on the Fc portions of the IgG molecule were the root of the anti-inflammatory activity. When the researchers removed the sialic acid, the molecule retained its structure and its half-life, but it lost its protective abilities. "This is a very interesting condition that's set up," Ravetch says. "IgG can shift from a state that is quite inflammatory to a state that is actively anti-inflammatory by just changing a sugar." This switch occurs during a normal immune response to a foreign substance, shifting the IgG antibodies from an anti-inflammatory state to one that is pro-inflammatory and able to efficiently dispose of the foreign challenge.

To test the theory, Ravetch and his colleagues tried enriching IVIG for the IgG molecules that contained sialic acid. They found that just enriching for this IgG species increased IVIG activity by a factor of ten, while removing it wiped out the therapeutic activity altogether. This discovery, Ravetch says, has potentially huge implications, and his lab is now working to generate a recombinant form of IgG that, by virtue of a sialic acid molecule attached in the right place, will be anti-inflammatory and could act as a novel treatment for autoimmune disorders. "We have the opportunity to make a much better form of IVIG that will work 100 times better and be a pure molecule -- to build a much better class of therapeutics based on a property that already exists in nature."

(Source: Newswise)
'"/>




Related medicine news :

1. Single gene analysis for diagnosis of a range of blood disorders
2. Single drug for bipolar disorder
3. Treating Testicular Cancer With A Single Dose Of Chemotherapy
4. Decreasing Multiple Births By Single Embryo Transfers
5. Single gene skin cancer cause
6. Drug Firms To Produce Single Pill AIDS Treatment
7. Malaria May Gain Resistance To Single Drug Prescriptions
8. Single Women with Baby Cravings Can Actually Cradle their Own, Courtesy NHS
9. Thai Doctors Removed 421 Kidney Stones From A Single Person
10. Single Dose Of Azithromycin Could Cure Trichiasis
11. Effects Of Certain Food Related To Single Pain Receptors
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:10/12/2017)... ... October 12, 2017 , ... ... healthcare compliance program management, will showcase a range of technology and learning solutions ... Living (NCAL) Convention and Expo to be held October 14–18, 2017 at the ...
(Date:10/12/2017)... ... October 12, 2017 , ... The ... demand of today’s consumer and regulatory authorities worldwide. From Children’s to Adults 50+, ... to meet the highest standard. , These products are also: Gluten Free, ...
(Date:10/12/2017)... ... ... Asante, a nationally recognized health system in southern Oregon, ... health joint venture through an agreement, effective October 1, 2017, to create AccentCare ... company with Asante, delivering clinically integrated care, for the past eight years. This ...
(Date:10/12/2017)... ... ... HMP , a leader in healthcare events and education, today announced that ... for ‘Best B-to-B Healthcare Website.’ Winners were announced during the Eddie & Ozzie Awards ... recognizes editorial and design excellence across a range of sectors. This year’s program included ...
(Date:10/12/2017)... , ... October 12, 2017 , ... ... named one of Michigan’s 2017 Best and Brightest in Wellness® by Best and ... Wellness® awards program on Friday, Oct. 20 from 7:30 a.m. to 2 p.m. ...
Breaking Medicine News(10 mins):
(Date:9/28/2017)... , Sept. 28, 2017 Cohen Veterans ... advance the use of wearable and home sensors for ... disorders. Early Signal Foundation, a nonprofit organization focused on ... will provide an affordable analytical system to record and ... ...
(Date:9/23/2017)... Janssen Biotech, Inc. (Janssen) announced today that ... U.S. Food and Drug Administration (FDA) for the Biologics ... treatment of moderately to severely active rheumatoid arthritis (RA). ... needed to further evaluate the safety of sirukumab in ... "We are disappointed ...
(Date:9/18/2017)... Pa. and KALAMAZOO, Mich. , Sept. 18, ... , and OptiMed Specialty Pharmacy of ... to offer a strategic hub service that expedites and ... sought-after personal spirometer, Spiro PD 2.0, and wellness management ... spirometer is a medical device used to measure lung ...
Breaking Medicine Technology: