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:6/25/2016)... ... June 25, 2016 , ... Experts from the ... AcademyHealth’s Annual Research Meeting June 26-28, 2016, at the Hynes Convention Center in ... topics including advance care planning, healthcare costs and patient and family engagement. , ...
(Date:6/25/2016)... ... June 25, 2016 , ... "With 30 hand-drawn hand gesture animations, FCPX ... Austin - CEO of Pixel Film Studios. , ProHand Cartoon’s package transforms over ... Cut Pro X . Simply select a ProHand generator and drag it above media ...
(Date:6/25/2016)... ... June 25, 2016 , ... Dr. Calvin Johnson has dedicated ... has implemented orthobiologic procedures as a method for treating his patients. The procedure ... doctors to perform the treatment. Orthobiologics are substances that orthopaedic surgeons use to ...
(Date:6/24/2016)... ... June 24, 2016 , ... A recent article published June ... with. The article goes on to state that individuals are now more comfortable seeking ... common operations such as calf and cheek reduction. The Los Angeles area medical group, ...
(Date:6/24/2016)... ... ... was in a crisis. Her son James, eight, was out of control. Prone to extreme ... “When something upset him, he couldn’t control his emotions,” remembers Marcy. “If there was ... other children and say he was going to kill them. If we were driving ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... -- Research and Markets has announced the addition ... - Forecast to 2022" report to their offering. ... to date financial data derived from varied research sources to ... potential impact on the market during the next five years, ... of sub markets, regional and country level analysis. The report ...
(Date:6/23/2016)... Research and Markets has announced the ... report to their offering. ... favourable commercial environment for MedImmune to enter. The US ageing ... serve to drive considerable growth for effective anti-influenza medications. The ... sales considerably, but development is still in its infancy. ...
(Date:6/23/2016)... , June 23, 2016 , ... on Thursday, July 7, 2016 , , , , LOCATION: ... , , , , EXPERT PANELISTS:  , , , ... Senior Industry Analyst, Christi Bird; Senior Industry Analyst, Divyaa Ravishankar and ... The global pharmaceutical industry is witnessing an exceptional era. ...
Breaking Medicine Technology: