Featured Research

from universities, journals, and other organizations

License To Kill: Development Of Killer T Cells Observable

Date:
November 25, 1999
Source:
Harvard Medical School
Summary:
Researchers at the Center for Blood Research and Harvard Medical School report in the November 23 Proceedings of the National Academy of Sciences the development of an animal model that literally illuminates one of the most dramatic and, until now, obscure events in the body: how the immune system turns immature T cells into specialized killer, or cytotoxic, T cells, capable of seeking out and destroying cells maimed by cancer and infection.

New Model Could Show How Immune System is Thwarted By HIV and Cancer

Related Articles


Boston, MA--November 22, 1999--Researchers at the Center for Blood Research and Harvard Medical School report in the November 23 Proceedings of the National Academy of Sciences the development of an animal model that literally illuminates one of the most dramatic and, until now, obscure events in the body: how the immune system turns immature T cells into specialized killer, or cytotoxic, T cells, capable of seeking out and destroying cells maimed by cancer and infection.

"Now, we have a model that makes it possible to look at a unique and important subset of cells; first to identify it and then analyze it in novel ways," says Ulrich von Andrian, MD, PhD, HMS associate professor of pathology. "This system might allow us to get a better understanding of what provides the T cells' license to kill," he says. Ultimately, the model could be used to clarify such diseases as cancer and AIDS. Some researchers have suspected that viruses and tumor cells may thwart the immune system by taking away T cells' license to kill—that is, by sabotaging the cellular machinery that enables them to attack unwanted cells.

"During the initial stages of an HIV infection, there are lots of cytotoxic T cells in the body but, for some reason, they are not able to contain the infection," says N. Manjunath, PhD, research fellow, and lead author of the study. "Is there a defect in these cells? Understanding normal differentiation with our new model, we might help answer this question."

One of the biggest obstacles to understanding this crucial transformation has been spotting members of this elite corps in large enough numbers to study them. Relatively rare—white blood cells in general number about one in one thousand cells in the bloodstream—T cells also move with the same velocity as other cells in the blood so they tend to get lost in the crush.

To flush them out, von Andrian, Manjunath, and their colleagues created a mouse in which immature T cells were equipped, by genetic means, with a green fluorescent tag. Normally, immature, or naive, T cells learn to identify bits of foreign invaders, called antigens, early on, but develop into fully effective killer T cells—complete with the cellular machinery to kill—only when they encounter actual infection. To coax the quiescent killer T cells into their fully effective state, the researchers infected the mice with a virus. Upon reaching full maturity, almost all of the cells lost their green tag—essentially revealing themselves by becoming invisible.

Why the green light goes out in the mature T cells is not clear but it could be a by-product of other changes occurring inside the differentiating T cells—perhaps the removal of factors that help to drive green fluorescent protein expression. Some or all of these factors may control other genes which need to be turned off in order for the killer T cell to differentiate. Identifying these factors and the genes they control will be "a milestone forward towards understanding how killer T cells develop," says Manjunath.


Story Source:

The above story is based on materials provided by Harvard Medical School. Note: Materials may be edited for content and length.


Cite This Page:

Harvard Medical School. "License To Kill: Development Of Killer T Cells Observable." ScienceDaily. ScienceDaily, 25 November 1999. <www.sciencedaily.com/releases/1999/11/991125090414.htm>.
Harvard Medical School. (1999, November 25). License To Kill: Development Of Killer T Cells Observable. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/1999/11/991125090414.htm
Harvard Medical School. "License To Kill: Development Of Killer T Cells Observable." ScienceDaily. www.sciencedaily.com/releases/1999/11/991125090414.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Best Tips to Curb Holiday Carbs

The Best Tips to Curb Holiday Carbs

Buzz60 (Dec. 19, 2014) It's hard to resist those delicious but fattening carbs we all crave during the winter months, but there are some ways to stay satisfied without consuming the extra calories. Vanessa Freeman (@VanessaFreeTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Sierra Leone Bikers Spread the Message to Fight Ebola

Sierra Leone Bikers Spread the Message to Fight Ebola

AFP (Dec. 19, 2014) More than 100 motorcyclists hit the road to spread awareness messages about Ebola. Nearly 7,000 people have now died from the virus, almost all of them in west Africa, according to the World Health Organization. Video provided by AFP
Powered by NewsLook.com
Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
The Best Protein-Filled Foods to Energize You for the New Year

The Best Protein-Filled Foods to Energize You for the New Year

Buzz60 (Dec. 19, 2014) The new year is coming and nothing will energize you more for 2015 than protein-filled foods. Fitness and nutrition expert John Basedow (@JohnBasedow) gives his favorite high protein foods that will help you build muscle, lose fat and have endless energy. Video provided by Buzz60
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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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