[Ultrasound of a spleen by Nevit Dilmen via Wikimedia Commons & CC 2.0]
Blood moves fast. It only takes about 20 seconds for a red blood cell to make a full circuit through your entire body, and your blood makes that journey thousands of times each day.
The speed of the blood stream is a challenge for scientists who study how the body copes with invading bacteria. Normally, the bloodstream is devoid of microbial interlopers, but when bacteria do break into the blood stream, they can be extremely dangerous. Sepsis, for example, occurs when the immune system tries to fight off a large number of blood-invading bacteria. And sepsis kills up to half of the people who develop it, according to the NIH.
So when bacteria find their way into blood, your body wants to take them out ASAP. Blood-filtering organs like the liver, the kidneys, and the spleen have dedicated local immune cell task forces that help kill microbes, and of course, blood itself has loads of white blood cells on patrol.
But platelets–the globs of gunk that form scabs on wounds–also trap bacteria. When the bacteria are whizzing through the bloodstream, sometimes they collide with a platelet and get stuck to it. But according to a recent study in Cell Host and Microbe, getting stuck to a platelet doesn’t kill the bacteria.
Instead, the platelets carry their trapped bacteria through the bloodstream until they wash up at the spleen, says the study’s senior co-author Admar Verschoor from University of Lubeck in Germany.