Scientists at the University of Calgary’s Faculty of Medicine have discovered a mechanism that is used to protect the body from harmful bacteria. Platelets, a component of blood typically associated with clotting, were discovered to actively search for specific bacteria, and upon detection, seal it off from the rest of the body. The findings, which were published in Nature Immunology this week, provide the science community with a greater understanding of immunity.

“The science community has known that platelets do participate in immunity, but now it’s been demonstrated that they have a way of actively searching for bacteria,” says Craig Jenne, PhD, one of the authors of the study and a member of the university’s Snyder Institute for Chronic Diseases.

The vast majority of bacteria in the blood stream is trapped by the liver in a network of specialized cells known as Kupffer cells. Once trapped, a series of immune processes take place to eradicate the bacteria; however, this can take several hours, lending time to harmful bacteria to multiply and release toxins into the neighboring cells, subsequently causing infection and cell damage and death.

“Upon entering the blood stream, bacteria can start to divide within several minutes,” he says. “So if you’re waiting for the immune system to deal with it, the bacteria could become an infection before it gets there.”

Through imaging of the liver in animal models, scientists discovered that platelets are constantly interacting with the Kupffer cells by ‘touching’ them to search for captured bacteria. If nothing is detected, or if the bacteria isn’t deemed particularly harmful, the platelets will move on; however, if harmful bacteria is detected, the platelets will bind to it, sealing it off from the body until the immune system can rid the bacteria altogether. This happens within seconds of cell capture and thus reduces the likelihood of infection.

“If this instantaneous response didn’t exist, it could be a matter of life and death,” he says.

Interestingly, it was observed that while this touch-and-go mechanism is happening continuously, platelets only appear to create this barrier around particularly harmful bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). MRSA can lead to serious and potential fatal conditions such as sepsis, and is spread through skin to skin contact.

“We now have a completely different angle of how the immune system deals with specific types of bacteria,” says study author Paul Kubes, PhD, who is also director of the Snyder Institute for Chronic Diseases. “Going forth we can begin to look at how we can help our own defenses deal with these types of bacteria.”

Source: University of Calgary

Today’s NASA Breaking News:

• Kansas Students to Speak Live With Space Station NASA Astronauts
  Expedition 36 crew members and NASA astronauts Chris Cassidy and Karen Nyberg, currently orbiting aboard the International Space Station, will speak with students gathered at the Kansas Cosmosphere and Space Center at 9:40 a.m. CDT (10:40 a.m. EDT), Wednesday, June 19.
• Cassini Probe to Take Photo of Earth From Deep Space
  NASA’s Cassini spacecraft, now exploring Saturn, will take a picture of our home planet from a distance of hundreds of millions of miles on July 19.
• NASA Announces Asteroid Grand Challenge
  NASA announced Tuesday a Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them.

The 2013 astronaut candidate class comes from the second largest number of applications NASA ever has received — more than 6,100. The group will receive a wide array of technical training at space centers around the globe to prepare for missions to low-Earth orbit, an asteroid and Mars.

“These new space explorers asked to join NASA because they know we’re doing big, bold things here — developing missions to go farther into space than ever before,” said NASA Administrator Charles Bolden. “They’re excited about the science we’re doing on the International Space Station and our plan to launch from U.S. soil to there on spacecraft built by American companies. And they’re ready to help lead the first human mission to an asteroid and then on to Mars.”

Watch Administrator Bolden’s message about the Astronaut Class of 2013

The new astronaut candidates are:

Josh A. Cassada, Ph. D., 39, is originally from White Bear Lake, Minn. Cassada is a former naval aviator who holds an undergraduate degree from Albion College, and advanced degrees from the University of Rochester, N.Y. Cassada is a physicist by training and currently is serving as co-founder and Chief Technology Officer for Quantum Opus.

Victor J. Glover, 37, Lt. Commander, U.S. Navy, hails from Pomona, Calif., and Prosper, Texas. He is an F/A-18 pilot and graduate of the U.S. Air Force Test Pilot School. Glover holds degrees from California Polytechnic State University, San Luis Obispo, Calif.; Air University and Naval Postgraduate School. He currently is serving as a Navy Legislative Fellow in the U.S. Congress.

Tyler N. Hague (Nick), 37, Lt. Colonel, U.S. Air Force, calls Hoxie, Kan., home. He is a graduate of the U.S. Air Force Academy, Massachusetts Institute of Technology, and the U.S. Air Force Test Pilot School, Edwards, Calif. Hague currently is supporting the Department of Defense as Deputy Chief of the Joint Improvised Explosive Device Defeat Organization.

Christina M. Hammock, 34, calls Jacksonville, N.C. home. Hammock holds undergraduate and graduate degrees from North Carolina State University, Raleigh, N.C. She currently is serving as National Oceanic and Atmospheric Administration (NOAA) Station Chief in American Samoa.

Nicole Aunapu Mann, 35, Major, U.S. Marine Corps, originally is from Penngrove, Calif. She is a graduate of the U.S. Naval Academy, Stanford (Calif.) University and the U.S. Naval Test Pilot School, Patuxent River, Md. Mann is an F/A 18 pilot, currently serving as an Integrated Product Team Lead at the U.S. Naval Air Station, Patuxent River.

Anne C. McClain, 34, Major, U.S. Army, lists her hometown as Spokane, Wash. She is a graduate of the U.S. Military Academy at West Point, N.Y.; the University of Bath and the University of Bristol, both in the United Kingdom. McClain is an OH-58 helicopter pilot, and a recent graduate of U.S. Naval Test Pilot School at Naval Air Station, Patuxent River.

Jessica U. Meir, Ph.D., 35 is from Caribou, Maine. She is a graduate of Brown University, has an advanced degree from the International Space University, and earned her doctorate from Scripps Institution of Oceanography. Meir currently is an Assistant Professor of Anesthesia at Harvard Medical School, Massachusetts General Hospital, Boston.

Andrew R. Morgan, M.D., 37, Major, U.S. Army, considers New Castle, Pa., home. Morgan is a graduate of The U.S. Military Academy at West Point, and earned doctorate in medicine from the Uniformed Services University of the Health Sciences, Bethesda, Md. He has experience as an emergency physician and flight surgeon for the Army special operations community, and currently is completing a sports medicine fellowship.

The new astronaut candidates will begin training at NASA’s Johnson Space Center in Houston in August.

“This year we have selected 8 highly qualified individuals who have demonstrated impressive strengths academically, operationally, and physically” said Janet Kavandi, director of Flight Crew Operations at Johnson Space Center. “They have diverse backgrounds and skill sets that will contribute greatly to the existing astronaut corps. Based on their incredible experiences to date, I have every confidence that they will apply their combined expertise and talents to achieve great things for NASA and this country in the pursuit of human exploration.”

Souce: NASA