London: It`s known that platelets primarily help blood to clot. Now it appears they are also key to forming a full-blown immune response, say scientists.
When bacteria enter blood, they rapidly become coated in platelets, the `New Scientist` quoted as saying Dirk Busch, who led a team at the University of Munich in Germany which carried out the research into platelets.
These sticky cell fragments then direct bacteria to the spleen, where they are engulfed by dendritic cells – immune cells that trigger a full-blown immune response, according to the scientists.
This process relies on the interaction between a platelet receptor called GPIb and a blood protein called C3, which sticks to bacteria.
When mice bred to lack C3 were injected with Listeria monocytogenes, platelets failed to surround the bacteria.
Instead, they were destroyed by a different immune cell, the macrophage, say the scientists.
Although the macrophages cleared the bacteria, the lack of C3 prevented the formation of immunological memory – which enables the immune system to remember foreign invaders and respond to a future attack.
Ultimately, Busch says it might be possible to boost platelet response to improve vaccines.
The findings have been published in the `Nature Immunology` journal.