Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cells on path to becoming mature T-cells more flexible than commonly thought

11.04.2008
Findings may shed light on T-cell leukemias and immunodeficiencies

Contrary to the currently accepted model of T-cell development, researchers at the University of Pennsylvania School of Medicine have found that juvenile cells on their way to becoming mature immune cells can develop into either T cells or other blood-cell types versus only being committed to the T-cell path. The findings appear in this week’s issue of Nature, and have implications for better understanding how T-cell leukemias and other disorders arise.

“It is critically important to understand the life history of the T-cell lineage and to define the steps that multipotent progenitor cells take to mature to T cells,” says lead author Jeremiah Bell, PhD, Postdoctoral Fellow in the Department of Laboratory Medicine and Pathology. “Whether you’re trying to understand T-cell immunodeficiencies, T-cell cancers, or other T-cell-related disorders, you first need to know the steps in T-cell development, and the signals acting at each step.”

The life of a T cell, and all other blood cells, begins in the bone marrow as a hematopoietic stem cell (HSC). HSCs have the potential to become all the different types of cells in the blood, including red blood cells, platelets, white blood cells, and all the cells involved in defending the body against pathogens and foreign proteins. The first stage in the process leading to such diversity is for the HSCs to become the precursor cells called multipotent progenitor (MPPs) cells.

The accepted version of what happens next is that there is a fork in the road to becoming a mature blood cell. Each MPP commits to becoming either a precursor of red cells and non-lymphoid white blood cells (called the myeloid pathway) or a precursor of T and B cells (called the lymphoid pathway). The T-cell precursors then go to the thymus, a small organ located under the breastbone, where they are called early thymic progenitors (ETPs).

“If the currently accepted model of T-cell development is correct, then early thymic progenitors, the ETPs, should be able to make T cells, but unable to make myeloid cells,” explains senior author Avinash Bhandoola, PhD, Associate Professor of Pathology and Laboratory Medicine. “Jeremiah instead found that progenitor cells that make it to the thymus have not yet committed to either the myeloid or T-cell pathway.”

In order to determine the potential of ETPs, the team first had to separate ETPs from all the other cells in a mouse thymus. This was accomplished by sorting the cells based on surface tags that are characteristic of the ETP cell type.

Next, single ETP cells were painstakingly placed into culture so that each container received only one cell. “We really wanted to examine single cells,” says Bell. “Otherwise, even if you do see T cells and myeloid cells, you can’t be certain that they all came from the same progenitor cell.” After growing and dividing for several days, the cells from each container were examined, again by surface tags, to see whether T cells or myeloid cells were present.

To the surprise of Bell and Bhandoola, most of the cultures begun with single cells had become a mixture of T cells and myeloid cells. This means that the majority of early thymic progenitor cells do not commit to becoming T cells by the time they get to the thymus gland. ETP cells retained the ability to become either T cells or myeloid cells.

Since ETPs showed the potential to give rise to myeloid cell types, the team also asked whether some of the myeloid cells in the thymus normally arise from ETPs. The process of T-cell development in the thymus requires progenitor cells to rearrange pieces of DNA. This process of DNA rearrangement is required to build the antigen receptor used by T cells, and permanently marks ETPs. Bell and Bhandoola found that permanent marks of past DNA rearrangements were present in myeloid cells within the thymus, but not in myeloid cells at other sites. This showed that ETPs give rise to myeloid cells in the normal thymus. “It’s very hard to accommodate these data with our old way of thinking about T-cell development,” notes Bhandoola.

“Now, we want to understand how ETPs make the decision to become myeloid cells or T cells within the thymus,” says Bell. “Although our research is focused on basic science, it is relevant to figuring out how T-cell leukemias develop from early progenitor cells.”

“We’re also wondering about the myeloid cells in the thymus that arise from ETPs,” adds Bhandoola. “Are they doing something we need to know about, and what could that be?”

Karen Kreeger | EurekAlert!
Further information:
http://www.uphs.upenn.edu

Further reports about: Bhandoola Development ETP HSC MATURE Precursor T cells Thymus blood cells myeloid progenitor

More articles from Life Sciences:

nachricht Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

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....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

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

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>