Limulus amoebocyte lysate, more commonly known as LAL is a vital product to the medical industry. Anytime you have blood taken, know the needle was tested for endotoxin contamination using the LAL test. In fact, everything from prosthetic limbs to vaccines are tested for contamination with LAL. Where does this miracle come from? A 350 million year old friend.
In 1956 MBL scientist Fred Bang was studying circulatory systems using the horseshoe crab. He noticed a few crabs died of a strange complication; most of their blood clumped together in clots throughout the body. Although it sounds like the sci-fi story of The Andromeda Strain, Bang discovered a immune system mechanism so old, it predates antibodies.
This immune defense is dependent on amoebocytes in the crab's blood. These amoebocytes contain many granules in their cytoplasm. Normally these amoebocytes perform phagocytotic functions but when the presence of endotoxins, a byproduct of bacteria is detected they act in an entirely different way. The cells undergo such radical changes, initially researchers believed the horseshoe crab possessed several types of blood cells. The cytoplasm and granules streaming from the cell empty the cell of its contents, altering it's shape. The granules contains coagulogen, which causes clotting immdiately in the surrounding areas. This prevents bacteria from invading the crab's partially open circulatory system.
Fortunately for humans, this process works with extracted limulus amoebocyte lysate. The extraction and selling of LAL is a 50-60 million dollar industry. The FDA requires that injectable drugs and vaccines be tested with LAL before they are approved. LAL testing insures the saftey of medical equipment that saves lives.
Unfortunately for humans, the horseshoe crab population is on the decline. Over fishing is severely depleting the crab population, found only on the east coast, primarily in Delaware Bay. The biomedical industry is not the culprit, however. The fishing industry catches the crabs to bait eel and conch traps killing over two millions crabs a year. The medical industry catches the crabs, bleeds about on third of their blood, then releases them within 36 hours. The mortality rate is about 7.5 to 10%. There is no synthetic duplicate of LAL, conservation and responsible management of the horseshoe crab not only benefits everyone, it might save your life.