Navigation Links
Immune memory formation seen in early stages of viral infection
Date:1/28/2010

In an acute viral infection, most of the white blood cells known as T cells differentiate into cells that fight the virus and die off in the process. But a few of these "effector" T cells survive and become memory T cells, ensuring that the immune system can respond faster and stronger the next time around.

Scientists have identified a molecule that defines which cells are destined to become memory T cells just a few days after a viral infection begins. The finding could guide the development of more effective vaccines for challenging infections such as HIV/AIDS and also cancer.

The results were published online this week by the journal Immunity. The senior author is Rafi Ahmed, PhD, director of the Emory Vaccine Center, a Georgia Research Alliance Eminent Scholar and a member of the National Academy of Sciences.

Working with Ahmed, postdoctoral fellows Vandalia Kalia and Surojit Sarkar tracked memory T cell formation in mice infected with lymphocytic choriomeningitis virus, a virus that causes an acute infection. They observed that a few days after infection begins, T cells separate into two groups: one with high levels of the molecule CD25 on their surfaces and one with low levels of CD25. Later on, all T cells reduce their levels of CD25 and the differences disappear as the infection is cleared.

"The outstanding question in our field has been: when do T cells commit to becoming memory cells," Kalia says. "This is one of the earliest points where we have been able to see these groups of cells with distinct fates."

CD25 is a molecule on the outside of cells that allows them to respond more sensitively to interleukin 2 (IL2), a growth factor that stimulates T cells. IL2 regulates immune activation. The most commonly used drugs to control the immune systems of transplant patients tamp down production of IL2.

During viral infection, cells with more CD25 respond to IL2 more strongly and produce more battle-ready progeny, but they don't stick around. Cells with low levels of CD25 are five times more able to persist long-term, and they also acquire the ability to travel throughout the body's lymph nodes key properties of memory T cells compared to effector cells.

"Apparently, cells that receive prolonged IL-2 signals are pushed further down the effector path and hence exhibit decreased potential to form long-lived memory cells," Sarkar says. "It may be beneficial that not all of the T cells burn themselves out fighting the virus so that memory-fated cells can conserve resources for the next encounter."

When mice are given extra IL2, T cells exhibit more pronounced effector characteristics. Sarkar says the results will be instructive for researchers developing vaccines because, combined with previous observations in the field, they show that both too much IL2 and its absence can be detrimental to the development of immunological memory. Because IL-2 is a key regulator of the immune system, some clinical studies have examined whether IL2 can boost immune responses against HIV and cancer, for example.

The differences between the groups of T cells may arise because not all T cells get the same level of stimulation as the infection progresses, Kalia says. "In this situation, a spectrum of effector cells with a range of differentiation states and memory potential likely develops," she says.


'/>"/>

Contact: Holly Korschun
hkorsch@emory.edu
404-727-3990
Emory University
Source:Eurekalert

Related medicine news :

1. Immune Deficiency Foundation Praises ACHDNC Recommendation for SCID Screening in Newborns
2. Immune Response Better With Skin Scratch Vaccination
3. Cancer stem cells suppress immune response against brain tumor
4. MBM ScienceBridge GmbH Negotiates License Agreement Between the Georg-August-University Gottingen, Universitatsmedizin, the University of Regensburg, and the UKs Medical Research Council Technology for a New Therapy of Inflammatory and Immune Disea
5. NEI Guided Nutrition Program(TM) is Second Entrant in Medical Arsenal for Neuro-Endocrine-Immune Supersystem(C) Product and Testing Protocols
6. Immune responses to tetanus vaccine unchanged for RA patients on rituximab
7. Free Sample of Proven Health Mushroom Supplement Offered By ImmuneResponse247.com
8. Immune cell activity linked to worsening COPD
9. Reportlinker Adds The Future of Autoimmune Diseases Therapeutics - Market Forecasts to 2015, Competitive Benchmarking, Product Pipeline and Deals Analysis
10. DNA Test May Detect Immune Disorder in Infants
11. Bortezomib shows promise in reducing GVHD and reconstituting immune system in some patients
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/5/2016)... Chicago, Illinois (PRWEB) , ... February 05, 2016 ... ... advisors and independent PROSHRED franchises from across the country gathered at the La ... to recognize top performers. PROSHRED Chicago was named the year’s most outstanding ...
(Date:2/5/2016)... ... 05, 2016 , ... Boar’s Head Brand®, one of the nation’s leading providers ... Game. Take the stress out of your party preparation – follow these easy, yet ... stage of the game. , “The key to hosting a successful game-day party is ...
(Date:2/5/2016)... ... 05, 2016 , ... Stuart Bentkover, MD, FACS is thrilled to ... the most effective tattoo removal today, Dr. Bentkover is the only doctor in Central ... the PicoSure has been approved by the Food and Drug Administration (FDA) as a ...
(Date:2/5/2016)... (PRWEB) , ... February 05, 2016 , ... Health and ... more relevant to individuals in the event they are experiencing an illness. Migraines are ... Those Americans that are afflicted with migraines would not wish the pain on their ...
(Date:2/5/2016)... ... 2016 , ... KICVentures ( http://www.kicventures.com ) announced today that ... York City on Thursday, January 21, 2016. Kingsley R. Chin, the CEO ... the varsity Columbia soccer program) spoke at the event, offering professional insight based ...
Breaking Medicine News(10 mins):
(Date:2/5/2016)... Calif. , Feb. 5, 2016  Syneron ... global aesthetic device company, announced today that ... Candela North America, is scheduled to participate in ... Healthcare Conference on February 11, 2016 in ... will allow institutional investors to meet with the ...
(Date:2/5/2016)... 5, 2016  Patients in Alabama ... (HIFU) therapy no longer have to travel out of state. ... with Urology Centers of Alabama to provide a ... for qualifying patients. Alabama ... treatment of prostate cancer using many different modalities. They are ...
(Date:2/5/2016)... 5, 2016 Aethlon Medical, Inc. (Nasdaq: AEMD ... CEO, will be presenting at Source Capital Group,s 2016 Disruptive ... at 2:15 p.m. ET on Wednesday, February 10, ... discussion taking place at 3:15 p.m. ET. http://www.aethlonmedical.com ... hour after the conclusion of the live event. The panel ...
Breaking Medicine Technology: