Endangered horseshoe crabs could lead the charge in pharma’s animal-free future

Horseshoe crabs have survived over 300 million years, outliving disease outbreaks, mass extinction events and the dinosaurs. But beginning in the 1960s, the crabs faced a daunting new threat.

With the discovery that their sky-blue blood forms clots when exposed to toxic bacteria, a primitive immune reaction designed to trap bacterial invaders, the crabs became an integral part of the biopharmaceutical apparatus. Now, the industry uses the blood to make limulus amebocyte lysate tests that screen drugs for dangerous endotoxins, which are impervious to standard heat sterilization methods.