Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Transplants - are mice leading the way?

05.07.2004


A new protocol for bone marrow transplants, which does not require the destruction of the recipient’s immune system before transfer of the new bone marrow, is described by a group of Oxford scientists in the 6th of July issue of the Proceedings of the National Academy of Sciences of the United States of America.

Furthermore, Luis Graça, Alain Le Moine, Herman Waldmann and colleagues from the University of Oxford, UK also found that following bone marrow transplant it is possible to successfully transplant other organs from the same donor, including skin, the most difficult organ to be successfully transplanted, into this now hybrid/chimeric bone marrow recipient.

The number of human tissue transplants is on the increase all over the world. In Europe, hundreds of thousands of tissue transplants are performed each year, while only in 1999 as many as 750 000 people in the United States of America received human tissue, twice as many as in 1990.



Graça, Le Moine and Waldmann’s team have been working with mice for a number of years to find alternative protocols for safer and more effective organ transplantations.

Because the immune system has evolved to react against any foreign intruder while remaining non-responsive against its own body, organs from other individuals are seen as foreign and so potentially dangerous which leads to their rapid destruction by the immune system, the body’s defence mechanism. This creates serious problems in clinical transplantation and until now only the use of strong immunosuppressive drugs permits relative transplantation success. This however is not ideal, not only because rejection frequently occurs but also because these drugs compromise the entire immune system making individuals much more susceptible to infection or cancer.

Graça, Le Moine and colleagues work on an alternative model of tolerance based on the use of antibodies against several proteins found in the cells involved in organ rejection. Although the idea of antibodies is not new, these have been mostly used to delete entire populations of cells involved in the graft rejection process. This has the disadvantage of creating “ holes” in the immune system and, like the immunosuppressive therapies widely used in transplant, increase the recipient/host’s disease susceptibility.

What is interesting about the Oxford’s scientists work is that their antibodies do not seem to kill the host cells involved in organ rejection but instead apparently re-programme these cells rendering them tolerant to the foreign organ while leaving the remaining immune system intact and fully operational. It is this specificity of the treatment, the capacity of only making tolerant the cells specific for the foreign organ while keeping the remaining immune system undamaged, that makes Graça, Le Moine and colleagues’ work so exciting.

However, it is still not clear what the mechanism is behind this organ-specific tolerance and this has created problems to the development of human therapies. In the work now published, Graça, Le Moine and colleagues investigate claims that CD4+CD25+ TCR+ cells, a group of cells of the immune system called this way because they express in their cellular membrane the three proteins: CD4, CD25 and TCR, are capable of regulating specific parts of the immune system without affecting the remaining immune cells and might be the cells responsible for inducing the type of organ transplant tolerance observed after Graça and Le Moine’s antibody therapy.

Unfortunately, the results by the team of scientists do not support the hypothesis. Nevertheless, this is still a very important result as it undoubtedly challenges the wide spread assumption that these cells are main regulators of immune responses.

Furthermore, Graça, Le Moine and colleagues also describe a new protocol for bone marrow transplantation and successfully achieve a skin graft transplant between totally different donors and recipients something never achieved before without immune deletion.

In fact, the team of scientists show how a course of their non-depleting antibodies, which are specific for proteins found on the membrane of the cells involved in graft rejection, when given at the same time as a bone marrow transplant, leads to complete acceptance of this foreign bone marrow. This is extraordinarily important as the normal protocol for bone marrow transplants require at least partial destruction of the recipient immune system so the new bone marrow would not be rejected.

Graça, Le Moine and colleagues also show for the first time that skin from a fully foreign donor is also accepted if this organ is transplanted together with bone marrow cells from the same donor while receiving the team’s set of tolerogenic antibodies.

These results are extremely important first because they describe an alternative and much more effective protocol to control the immune system in bone marrow transplants. Secondly, their new protocol of transferring bone marrow together with the organ to transplant proved much more effective, to such a extent that even a totally foreign skin graft was successful, something which has never been accomplished before in the absence of immunosuppression. In a world where more and more transplants are necessary as result of an increasing aging population this is a critical breakthrough.

Finally, Graça, Moine and colleagues capacity of “ re-programme” the immune system without affecting its whole capacity to fight infection might prove extremely important also in other diseases where pathology results from deregulation of the immune system as it seems to be the case in diabetes, rheumatoid arthritis or multiple sclerosis.

Ana Paula Gravito | alfa
Further information:
http://www.oct.mct.pt

More articles from Life Sciences:

nachricht Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University

nachricht Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017
25.04.2017 | Laser Zentrum Hannover e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017 | Physics and Astronomy

Researchers invent process to make sustainable rubber, plastics

25.04.2017 | Materials Sciences

Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017

25.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>