Stunning Diversity of NK Cell Receptors found

[Sparrowhawk]

Saw this on my FB feed this morning. On rereading I see my title should probably have been Stunning Diversity in NK cell RECEPTORS found, apologies:

http://www.niaid.nih.gov/topics/immuneSystem/Pages/naturalKillerCells.aspx

Researchers Offer a Detailed Look at Natural Killer Cells
Study Provides a New Framework for Understanding Immunity in Health and Disease
An NIAID-funded study has revealed a vast diversity of natural killer cells previously unrecognized in the human immune system. Natural killer (NK) cells are important for antiviral and antitumor responses, and these findings may have important implications for the development of new therapies for infection and cancer. The study appears in the October 23, 2013 issue of Science Translational Medicine.

So I wasn't sure where they were going with this but it appears the main finding is there are not, as I had assumed, just one kind of NK cell. There are two main kinds, and amongst those there are a HUGE range of variations.

NK cells are important for immune surveillance, distinguishing foreign cells from healthy host cells, and killing virus-infected cells and tumor cells. NK cells are not identical, and subpopulations have different roles. The function of an NK cell is linked to the receptors expressed on its surface, which relay specific messages to the cell.

There are two types of NK receptors, activating and inhibitory. Activating receptors are needed for NK cells to respond to problems like infection and cancer. Inhibitory receptors are essential for NK cells to maintain self-tolerance —the prevention of an immune response against healthy cells in your body.

Prior to this study, the identification of NK cell subpopulations in people had been limited by technology. Cell types are typically sorted by fluorescence-based flow cytometry, a method where color-coded antibodies bind to receptors. This technique can generally identify up to 12 receptors on a single cell. Recently, new technology called mass cytometry, or cytometry by time-of-flight (CyTOF), has allowed for simultaneous identification of up to 40 receptors.

My bolds, above and below.

Results of Study
Using the new CyTOF technology, the researchers assessed a total of 28 unique receptors expressed in different combinations on the surface of human NK cells. Blood samples were examined from 12 unrelated people and 5 pairs of identical twins. Surprisingly, the researchers found that no phenotype, or combination of receptors, was dominant and no one population represented more than 7 percent of the total NK cell population. Overall, the researchers identified an unexpected and remarkable diversity of over 100,000 distinct NK cell phenotypes in the population, and predicted that a person may have between 6,000 to 30,000 phenotypes.

By comparing the NK cells of twins and unrelated people, the researchers inferred how the function of NK cells may be shaped by genetics versus the environment. The data suggest that the expression of inhibitory NK cell receptors is under genetic influence, whereas activating receptors are influenced by the environment. The researchers speculate that inhibitory receptors, which maintain self-tolerance, need stricter regulation through genetic control, while activating receptors must be more flexible in their response to environmental threats. However, more work must be done to clarify these relationships.

Holy NK cells batman, that potentially makes NK cell involvement in CFS/ME that much more complicated...or may simplify things if we learn only certain types of NK cells are involved.

 

[heapsreal]

Other cfs studies mention dim and bright nk cellsand its the nk bright cell ffunction thats commonly low. So maybe those who test normal nk function possibly have a low bright cell function they dont know about. This type of testing though is only a research test.

 

[snowathlete]

Could become an important finding. Thanks for posting.

 

[anciendaze]

Don't assume the expression of receptors is static. There is a great deal of modulation, both internal and external. The chief cell types to consider are NK , NK/T cells and dendritic cells. There is a great deal of communication between them.

Not only do NK cells play a vital role in innate immunity, they are also one key to the interface between innate and acquired immunity. In health, they generally avoid lymphoid tissue, but concentrate there in infection. Besides attacking infected cells, they will even destroy uninfected dendritic cells which seem to be promoting an undesirable response. This makes them very important in autoimmune disorders.

If all that were not enough, they play important roles in natural development, where destroying unwanted cells is as important as growing those desired. I suspect they are important in autism, due to the peculiar nature of human neurological development, which continues long after birth.

Humans are born in an unusually helpless state. Quite a number of mammals, e.g. pronghorns, are born with the ability to stand, walk and run within minutes after birth. Even marsupials are able to crawl to the pouch and find a nipple without a great deal of help. Human babies not only have trouble controlling their neck and limbs at birth, they also lack control of their eyes. (Part of the appeal of puppies or kittens may be the way they resemble our own young in this respect.) Problems with passage through the birth canal limit the amount of brain development which can take place prior to birth, even if there were no problem in getting useful environmental stimuli. This means a great deal of brain development must take place after the neonate has left an immunologically-privileged environment. This is precisely the point at which autism becomes manifest.