Navigation Links
Scientists identify new model Of NK cell development

Scientists here have made a major discovery that sheds new light upon the growth and development of human natural killer (NK) cells, powerful but somewhat mysterious components of the body's immune system that are the first line of defense against cancer and infectious diseases.

Scientists have believed for years that human NK cells are generated in bone marrow, but Michael Caligiuri, director of the OSU Comprehensive Cancer Center and the senior author of the study, says research in his laboratory shows that the precursors to NK cells are actually found in cellular nurseries deep inside the body's lymph nodes.

The findings, appearing in the Mar. 22 issue of the journal Immunity, may offer clinicians new direction in determining how to manipulate this cell type in enhancing immune responses to cancer.

"This study is fundamentally about understanding the immune system more fully so we can help patients," says Caligiuri.

A major arm of the body's defense system is made up of lymphocytes, cells that fall broadly into three categories ?T cells, B cells and NK cells.

Although all lymphocytes stem from a common source ?progenitor cells in the bone marrow ?they take different paths in developing into full-fighters in the immune system. For example, cells destined to become T cells, sophisticated and highly focused killer cells, are released into the bloodstream and migrate to the thymus where they learn their role. In contrast, B cells, which make antibodies, remain and mature in the bone marrow. Until now, scientists thought NK cells did the same.

But Caligiuri, working with Aharon Freud, the lead author of the study and a doctoral candidate in Caligiuri's laboratory, had noted other work showing that mice lacking lymph nodes also lacked NK cells. In addition, in earlier research in Caligiuri's laboratory, scientists had identified two distinct subsets of human NK cells (referred to as CD56 bright and CD56 dim cells) and they observed that the bright subset appeared much more frequently in lymph nodes than in bone marrow or circulating blood.

In other words, they had a hunch traditional thinking about the origin of human NK cells might be wrong.

In building a case to support their beliefs, they first identified the NK precursor cell, then, they measured the number of the precursors in different parts of the body. Through flow cytometry, they discovered that while NK precursors make up about 1 percent of bone marrow progenitor cells and 6 percent of circulating blood progenitor cells, they comprise virtually all of the progenitor cells found in lymph nodes.

Interestingly, Gerard Nuovo, a pathologist and co-author of the study, discovered that these novel NK precursor cells are not randomly strewn throughout the lymph nodes, but rather localized near special sites called parafollicular regions, rich in T cells and NK bright cells.

"We thought this was pretty interesting because we know that in order for these NK precursor cells to grow and differentiate, they need one of two cytokines, interleukin-2 or interleukin-15," says Freud. "So it may not be coincidental that two types of immune cells that make those substances ?T cells and dendritic cells ?just happen to reside in lymph nodes, too."

Freud also makes the provocative observation that lymph nodes, while full of CD56 bright cells, are significantly lacking in their counterparts, the CD56 dim cells.

"Our next goal is to determine if there is some developmental continuum at work here, supporting the notion that CD56 bright cells are really just immature CD56 cells," he adds.

"This study raises almost as many questions as it answers," says Caligiuri, "Finding these nursery sites of NK cells is just the first step. We feel this is the first solid evidence supporting a new model of NK cell development, but we also know that more work needs to be done to fill in some gaps."

Sti ll, the findings appear to offer important new information about NK killer cells that may ultimately be helpful in designing more effective treatments for cancer and other diseases says Caligiuri.

"NK cells are the 'minutemen' of the defense system ?the first to respond to an attack. The more we know about them, the more we can help them do their work. In cancer, as in other diseases, the sooner you intervene, the better."


Source:Ohio State University

Related biology news :

1. Scientists ID molecular switch in liver that triggers harmful effects of saturated and trans fats
2. Scientists Replicate Hepatitis C Virus in Laboratory
3. Scientists detect probable genetic cause of some Parkinsons disease cases
4. Scientists find missing enzyme for tuberculosis iron scavenging pathway
5. Scientists seek answers on what activates deadly anthrax spores
6. Yale Scientists Find MicroRNA Regulates Ras Cancer Gene
7. Scientists collaborate to assess health of global environment
8. Scientists decipher genome of fungus that can cause life-threatening infections
9. Scientists discover the cellular roots of graying hair
10. Scientists rid stem cell culture of key animal cells
11. Scientists develop new color-coded test for protein folding
Post Your Comments:

(Date:10/29/2015)... Oct. 29, 2015  Connected health pioneer, Joseph ... explosion of technology-enabled health and wellness, and the business ... The Internet of Healthy Things . ... smartphones even existed, Dr. Kvedar, vice president, Connected Health, ... care delivery, moving care from the hospital or doctor,s ...
(Date:10/27/2015)... Munich, Germany , ... (ASGM) automatically maps data from mobile eye tracking videos ... so that they can be quantitatively analyzed with SMI,s ... Germany , October 28-29, 2015. SMI,s Automated Semantic ... eye tracking videos created with SMI,s Eye Tracking ...
(Date:10/26/2015)... Oct. 26, 2015  Delta ID Inc., a company ... mobile and PC devices, announced its ActiveIRIS® technology powers ... NX F-02H launched by NTT DOCOMO, INC in ... the second smartphone to include iris recognition technology, after ... NX F-04G in May 2015, world,s first smartphone to ...
Breaking Biology News(10 mins):
(Date:11/26/2015)... CHESHAM , England , November 26, ... Lightpoint Medical, an innovative medical device company specializing in ... Euro grant from the European Commission as part of the ... enabling the company to carry out a large-scale clinical trial ... -->      (Logo: , ...
(Date:11/25/2015)... and HOLLISTON, Mass. , Nov. 25, ... HART ), a biotechnology company developing bioengineered organ ... Jim McGorry will present at the LD Micro ... at 2:30 p.m. PT. The presentation will be webcast ... days. Management will also be available at the conference ...
(Date:11/25/2015)... PORTLAND, Oregon , November 25, 2015 /PRNewswire/ ... Deep Market Research Report is a professional and ... Genomics industry.      (Logo: ... basic overview of the industry including definitions, classifications, ... analysis is provided for the international markets including ...
(Date:11/24/2015)... Nov. 24, 2015 Halozyme Therapeutics, Inc. (NASDAQ: HALO ... New York on Wednesday, December 2 at ... , president and CEO, will provide a corporate overview. ... at 1:00 p.m. ET/10:00 a.m. PT . ... will provide a corporate overview. --> th Annual ...
Breaking Biology Technology: