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

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 October 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 October 20, 2014).

Share This



More Health & Medicine News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How Nigeria Beat Its Ebola Outbreak

How Nigeria Beat Its Ebola Outbreak

Newsy (Oct. 20, 2014) The World Health Organization has declared Nigeria free of Ebola. Health experts credit a bit of luck and the government's initial response. Video provided by Newsy
Powered by NewsLook.com
Another Study Suggests Viagra Is Good For The Heart

Another Study Suggests Viagra Is Good For The Heart

Newsy (Oct. 20, 2014) An ingredient in erectile-dysfunction medications such as Viagra could improve heart function. Perhaps not surprising, given Viagra's history. Video provided by Newsy
Powered by NewsLook.com
Ebola Worries End for Dozens on U.S. Watch Lists

Ebola Worries End for Dozens on U.S. Watch Lists

Reuters - US Online Video (Oct. 20, 2014) Forty-three people who had contact with Thomas Eric Duncan, the first person diagnosed with Ebola in the U.S., were cleared overnight of twice-daily monitoring after 21 days of showing no symptoms. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Fauci: Ebola Protocols to Focus on Training

Fauci: Ebola Protocols to Focus on Training

AP (Oct. 20, 2014) Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, says he expects revised CDC protocols on Ebola to focus on training, observation and ensuring health care workers are more protected. (Oct. 20) Video provided by AP
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