Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Genetically modified parasite lets researchers probe immune system’s memory

21.10.2004


Researchers at Washington University School of Medicine in St. Louis and the University of Pennsylvania have found an immune system cell can "remember" a parasite’s attack and help the body mount a more effective defense against subsequent invasions by the same parasite.



The finding, published in the October issue of Nature Medicine, will likely aid efforts to develop a vaccine for Leishmania major, a parasite that infects approximately 12 million people worldwide, causing significant death and disfigurement. It may also help efforts to develop vaccines for other pathogens including AIDS and tuberculosis.

Scientists have known that successful recovery from Leishmania infection immunizes humans and animals against subsequent infection. But previous experiments led researchers to suspect that this immunity resulted from the presence of a very small population of parasites that remained in the host even after full recovery. Loss of this minimal parasite remnant seemed in some studies to result in loss of immunity.


For the new study, immunologists at the University of Pennsylvania infected mice with a genetically modified form of Leishmania created by microbiologists at Washington University School of Medicine. The modified Leishmania lacks an enzyme required for DNA synthesis and can be completely wiped out by the mouse immune system.

Researchers found that after the mice had cleared the Leishmania parasite, a type of T cell -- the CD4+ central memory T cell -- still reacted to the parasite in the test tube. Mice who never had Leishmania and were given injections of these T cells fought off the parasite more effectively than mice that didn’t get the T cells. "This partial immunization suggests that we may need to look at generating large populations of these memory T cells at the time of vaccination," says study coauthor Stephen Beverley, Ph.D., the Marvin A. Brennecke Professor and head of the Department of Molecular Microbiology.

Researchers also found evidence that another class of T cells may stay primed to fight a new infection when a small remnant population of parasites persists. Beverley speculates that the presence of this second type of T cell, along with the central memory T cell, may be key to providing full protection.

Senior investigator Phillip Scott, Ph.D., professor of microbiology and immunology at the School of Veterinary Medicine at the University of Pennsylvania, has conducted additional experiments that showed central memory T cells can maintain their "memory" of Leishmania and respond to new infections at least 5 months after initial infection.

Because T cells orchestrate the immune system’s fight against other diseases, including tuberculosis and AIDS, scientists believe the new insights will be help efforts to develop other vaccines. "We are so much better at understanding how the immune system responds than we are at making a vaccine," Beverley notes. "These new results may help us better direct the immune response toward long-term vaccination."

Michael C. Purdy | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Health and Medicine:

nachricht New study points the way to therapy for rare cancer that targets the young
22.11.2017 | Rockefeller University

nachricht Penn study identifies new malaria parasites in wild bonobos
21.11.2017 | University of Pennsylvania School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Underwater acoustic localization of marine mammals and vehicles

23.11.2017 | Information Technology

Enhancing the quantum sensing capabilities of diamond

23.11.2017 | Physics and Astronomy

Meadows beat out shrubs when it comes to storing carbon

23.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>