Navigation Links
Hide and seek signals

The white blood cells that fight disease and help our bodies heal are directed to sites of infection or injury by 'exit signs' chemical signals that tell them where to pass through the blood vessel walls and into the underlying tissue. New research at the Weizmann Institute, which appeared in Nature Immunology online, shows how the cells lining blood vessel walls may act as 'selectors' by hiding the signals where only certain 'educated' white blood cells will find them.

In previous studies, Prof. Ronen Alon and his team in the Immunology Department had found that near sites of inflammation, white blood cells rapidly crawl along the inner lining of the blood vessels with tens of tiny legs that grip the surface tightly, feeling for the exit sign. Such signs consist of migration-promoting molecules called chemokines, which the cells lining the blood vessels endothelial cells display on their outer surfaces like flashing lights.

In the new study, Alon and his team, including Drs. Ziv Shulman and Shmuel Cohen, found that not all chemokine signals produced by endothelial cells are on display. They observed the recruitment of subsets of immune cells called effector cells that are the 'special forces' of the immune system: They receive training in the lymph nodes, where they learn to identify a particular newly-invading pathogen and then return to the bloodstream on a search and destroy mission. Like the other white blood cells, effector cells crawled on tiny appendages along the lining of inflamed blood vessels near the site of pathogen entry, but rather than sensing surface chemokines, they used their legs to reach into the endothelial cells in search of the migration-promoting chemokines.

As opposed to the external exit signs, these chemokines were held in tiny containers vesicles inside the inflamed endothelial cell walls. The effector cells paused in the joins where several cells met, inserting their legs through the walls of several endothelial cells at once to trap chemokines as they were released from vesicles at the endothelial cell membrane. Once they obtained the right chemokine directives, the immune cells were quickly ushered out through the blood vessel walls toward their final destination.

The researchers think that keeping the chemokines inside the endothelial cells ensures, on the one hand, that these vital signals will be safe from getting washed away in the blood or eaten by various enzymes. On the other hand, it guarantees that only those effector cells with special training that can make the extra effort to find the signals will pass through.

Alon: 'We are now seeing that the blood vessel endothelium is much more than just a passive, sticky barrier it actively selects which recruited cells actually cross the barrier and which will not. The endothelial cells seem to play an active role in showing the immune cells the right way out, though we're not sure exactly how. Moreover, we think that tumors near blood vessels might exploit these trafficking rules for their benefit by putting the endothelial cells in a quiescent state or making the endothelium produce the 'wrong' chemokines. Thus, immune cells capable of destroying these tumors will not be able to exit the blood and navigate to the tumor site, while other immune cells that aid in cancer growth will.'

Contact: Yivsam Azgad
Weizmann Institute of Science

Related medicine news :

1. Epigenetic signals differ across alleles
2. Higher anxiety, depression among women may have basis in cell signals
3. Neuro signals study gives new insight into brain disorders
4. Effects of exercise on meal-related gut hormone signals
5. Atomic structure discovered for a sodium channel that generates electrical signals in living cells
6. Researchers discover that changes in bioelectric signals cause tadpoles to grow eyes in back, tail
Post Your Comments:
(Date:11/25/2015)... , ... November 25, 2015 , ... ... double board certified facial plastic surgeon specializing in both surgical and non-surgical treatments, ... The Skin Spa at Hobgood Facial Plastic Surgery. , Highly trained and ...
(Date:11/25/2015)... ... November 25, 2015 , ... Brillianteen, McGaw YMCA’s ... learning in its 65th Anniversary Brillianteen Revue, scheduled for March 4-6, 2016. Auditions ... 65 years, Brillianteen has been a treasured tradition for numerous families in the ...
(Date:11/25/2015)... PA (PRWEB) , ... November 25, 2015 , ... “While ... said an inventor, from Bronx, N.Y. “I thought there had to be a convenient ... invented the PROTECTOR. , The PROTECTOR enables disabled individuals to safely travel during cold ...
(Date:11/25/2015)... ... November 25, 2015 , ... Castlewood Treatment ... struggling with eating disorders as a result of the $20,000 raised at the ... at Fox Run Golf Club in Eureka, will help individuals who otherwise might ...
(Date:11/25/2015)... ... November 25, 2015 , ... "When I underwent ... bras were incredibly uncomfortable," said an inventor from Bronx, N.Y. "In order to ... the patent-pending RECOVERY BRA for added comfort and support. The bra is easier ...
Breaking Medicine News(10 mins):
(Date:11/26/2015)... 26, 2015 3D bioprinting market ... to a new report by Grand View Research Inc. Rising ... which demands kidney transplantation is expected to boost the market ... for organ transplantation. --> 3D bioprinting market ... to a new report by Grand View Research Inc. Rising ...
(Date:11/26/2015)... DUBLIN , November 26, 2015 ... has announced the addition of the  ... in the Global Cell Surface Testing ... Opportunities" report to their offering.  ... the addition of the  "2016 Future ...
(Date:11/26/2015)... Research and Markets ( ) has announced the ... Type (Dressings, Therapy Devices, Active Wound Care), Application (Surgical ... Geography - Global Forecast to 2020" report to ... --> The purpose of this report is to ... advanced wound care market. It involves deep dive analysis ...
Breaking Medicine Technology: