Featured Research

from universities, journals, and other organizations

New Method To Track Immune System Enzyme In Live Animals Developed

Date:
May 18, 2007
Source:
NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases
Summary:
Scientists have created two mouse strains that will permit researchers to trace, in a live animal, the activity of an enzyme believed to play a crucial role both in the normal immune response as well as autoimmunity and B cell tumor development.

In this picture of intestinal villi from one of the new mouse strains, plasma cells are tagged with yellow (green-appearing) fluorescent protein.
Credit: Image courtesy of NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases

Scientists supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) at the National Institutes of Health have created two mouse strains that will permit researchers to trace, in a live animal, the activity of an enzyme believed to play a crucial role both in the normal immune response as well as autoimmunity and B cell tumor development.

The enzyme, known as activation-induced cytidine deaminase or AID (which has no relation to the AIDS virus), is expressed by B cells, which are produced in the bone marrow and are responsible for making antibodies that attack foreign invaders such as viruses and bacteria. The enzyme enables the cells to respond with precision to the almost limitless types of invaders the body may encounter. Unfortunately, it also has a down side.

B cells constantly scan the body for foreign invaders, explains Rafael Casellas, Ph.D., an investigator in NIAMS’ Molecular Immunology and Inflammation Branch and lead author of the paper. As B cells encounter foreign antigens from viruses, bacteria or allergens, they migrate to germinal centers — specialized microenvironments in tonsils, spleen and lymph nodes. Within germinal centers, B cells divide extensively and express the AID enzyme, which causes random mutations and recombination in the cells’ immunoglobulin (antibody) genes. For the most part, these genetic changes are beneficial because they enable B lymphocytes to attack and stop the invader. In some cases, however, AID-dependent alterations in the genetic material of B cells can also lead to unwanted results such as autoimmunity and development of B cell tumors, as in the case of Burkitt lymphoma.

“It becomes crucial that we comprehend how AID is regulated during the normal immune response as well as in tumorigenesis and autoimmunity,” says Casellas. The problem with understanding how AID is regulated or deregulated is that there has not been an easy way to visualize the enzyme’s action in a living animal — until now.

To address this issue, Dr. Casellas and his colleagues created transgenic mice that had a green fluorescent protein derived from jellyfish fused to the AID enzyme. In these transgenic animals, B cells express the tagged enzyme during the immune response. In a second mouse strain, Casellas and coworkers expressed permanently a yellow fluorescent protein in the progeny of germinal center B cells. “Thanks to these new mouse models, we can track in live animals whenever the AID enzyme is active as well as the result of that activity,” says Casellas. Scientists can also cross these new mouse strains with mice predisposed to B-cell tumors or autoimmunity to see differences in enzyme expression in health and disease.

NIAMS Director Stephen I. Katz. M.D., Ph.D., believes these new tools have great potential to help solve some mysteries of the immune system, such as the causes of B-cell tumors and autoimmunity. “The better we understand these problems,” he says, “the closer we come to better treatments for them and eventually, perhaps, ways to prevent them.”

This work was also supported by the National Cancer Institute.

Article: Crouch E, et al. Regulation of AID expression in the immune response. J Exp Med 2007; 204:1145-1156.


Story Source:

The above story is based on materials provided by NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases. "New Method To Track Immune System Enzyme In Live Animals Developed." ScienceDaily. ScienceDaily, 18 May 2007. <www.sciencedaily.com/releases/2007/05/070517135405.htm>.
NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases. (2007, May 18). New Method To Track Immune System Enzyme In Live Animals Developed. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2007/05/070517135405.htm
NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases. "New Method To Track Immune System Enzyme In Live Animals Developed." ScienceDaily. www.sciencedaily.com/releases/2007/05/070517135405.htm (accessed April 19, 2014).

Share This



More Health & Medicine News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nine-Month-Old Baby Can't Open His Mouth

Nine-Month-Old Baby Can't Open His Mouth

Newsy (Apr. 19, 2014) Nine-month-old Wyatt Scott was born with a rare disorder called congenital trismus, which prevents him from opening his mouth. Video provided by Newsy
Powered by NewsLook.com
'Holy Grail' Of Weight Loss? New Find Could Be It

'Holy Grail' Of Weight Loss? New Find Could Be It

Newsy (Apr. 18, 2014) In a potential breakthrough for future obesity treatments, scientists have used MRI scans to pinpoint brown fat in a living adult for the first time. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
Powered by NewsLook.com
Scientists Create Stem Cells From Adult Skin Cells

Scientists Create Stem Cells From Adult Skin Cells

Newsy (Apr. 17, 2014) The breakthrough could mean a cure for some serious diseases and even the possibility of human cloning, but it's all still a way off. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins