Navigation Links
T-Cell Duplication Delayed Up to 3 Days After Infection

Finding challenges conventional theory on how immune system responds to invaders

FRIDAY, April 11 (HealthDay News) -- Immune system T-cells don't begin to multiply until up to three days after infection, an unexpected finding that changes current thinking about how the immune system responds to infection.

Researchers at the Scripps Research Institute in La Jolla, Calif., said this delay in T-cell proliferation may be an evolutionary safeguard against the risk of an autoimmune response caused by a sudden increase in T-cells.

It had been believed that memory T-cells (which recognize pathogens from previous infections) began to multiply much sooner than naive T-cells.

"It was thought that memory T-cells responded more effectively to infection by starting cell division earlier than naive cells and by multiplying more rapidly after that," Lindsay Whitton, a professor in the neuropharmacology department, said in a prepared statement. "Our study shows that neither assumption is true. Even though memory cells detected and responded to virus infection within a few hours, they did not begin to divide until after a lengthy delay. After that, cell division was rapid for both naive and memory cells."

Once proliferation of both types of cells started, there was a greater accumulation of memory T-cells, possibly because there were already more of them prior to infection, Whitton said.

The findings were published in April 10 online issue of the Public Library of Science Pathogens.

In this study, the Scripps team used laboratory animals to trace the proliferation of CD4 and CD8 memory T-cells. CD4 cells help regulate the immune system's response to pathogens such as bacteria and viruses, while CD8 cells attack infected cells and may be play a role in transplant rejection.

"The principal conclusions from our study are that, in a virus-infected animal, both naive and memory CD4 T-cells shows a similar and extended delay of approximately 72 hours before they begin to divide, and that this is true in both lymphoid and non-lymphoid tissues. This delay occurred despite the fact that the viral antigen reached T-cell-stimulatory levels within six to 12 hours after infection," Whitton said.

She and her colleagues "were very much surprised by the discovery that memory cells didn't begin proliferation sooner than their naive counterparts. Memory T-cells are central to the protective immunity of infections and vaccinations, because they act against subsequent encounters with specific microorganisms. Compared to naive cells, memory T-cells can be triggered by lower antigen levels, and their initial response to infection, such as the production of cytokines, is more rapid and more effective."

More information

The Nemours Foundation has more about the immune system.

-- Robert Preidt

SOURCE: Scripps Research Institute, news release, April 10, 2008

Copyright©2008 ScoutNews,LLC.
All rights reserved

Related medicine news :

1. Cells on path to becoming mature T-cells more flexible than commonly thought
2. Inverted DNA turns quiet developmental gene into a potent driver of t-cell lymphoma
3. Stimulating Thymus Reactivates T-Cell Production
4. EpiVax receives JDRF program funding to develop diabetes drug using natural regulatory T-cells
5. Tumors use enzyme to recruit regulatory T-cells and suppress immune response
6. A tumor of the pancreas mimicked by colonic duplication?
7. Less education may lead to delayed awareness of Alzheimers onset
8. Mandatory Accreditation Delayed Until September 2009
9. FDA Sunscreen Labeling Decision Delayed Another Month, Leading U.S. Physician to Say, Enough Is Enough
10. Wyeth Receives FDA Approval of Protonix for Delayed-Release Oral Suspension
11. Delayed angioplasty -- big bucks, no bang
Post Your Comments:
(Date:12/1/2015)... ... ... Royal River Natural Foods — a locally-owned, independent natural health store in ... nutritional supplement creatine, along with resistance training for a year, had more new bone ... report is part of the December 2015 issue of Natural Insights for Well Being®, ...
(Date:12/1/2015)... ... December 01, 2015 , ... According to an article ... filed a discrimination claim against the U.S. Department of Health and Human Services, claiming ... Act (ACA) plans are breaking the clause in the law prohibiting the denial of ...
(Date:12/1/2015)... ... December 01, 2015 , ... Califia Farms , one of ... iconic bottle has won top honors in Beverage World Magazine’s Global Packaging Design Awards, ... that it has been selected as a 2015 U.S.A. Taste Champion in the American ...
(Date:12/1/2015)... ... ... Growth in medical payments per workers’ compensation claim in Louisiana slowed from ... care, according to a recent study by the Workers Compensation Research Institute (WCRI). ... payments per claim with more than seven days of lost time continued to be ...
(Date:12/1/2015)... ... December 01, 2015 , ... CloudLIMS ... 2015 Golden Bridge Business Awards under the New Products and Services category for ... based sample management software that helps labs organize data and track ...
Breaking Medicine News(10 mins):
(Date:12/1/2015)... , Dec. 1, 2015 As enforcement of ... Chain Security Act (DSCSA) approaches, InfiniTrak ... independent pharmacies comply with looming FDA regulations. ... is entering endorsement agreements with State Pharmacy Associations, ... administration organization (PSAO) to exclusively provide the InfiniTrak ...
(Date:12/1/2015)... DUBLIN , Dec. 01, 2015 /PRNewswire/ ... announced the addition of the "Spinal ... Growth, Trends, and Forecast 2015 - 2023" ... ) has announced the addition ... - Pipeline Assessment, Size, Growth, Trends, and ...
(Date:12/1/2015)... -- Royal Philips  (NYSE: PHG, AEX: ... software that produces high-contrast images for all anatomies in ... at the 2015 Radiological Society of North America ... first digital imaging solution providing grid-like contrast improvement and ... and supports "first-time-right imaging" by decreasing the need for ...
Breaking Medicine Technology: