Prehistoric crabs help test vaccine safety

These relics from a bygone era, whose arrival preceded the dinosaurs, have been dwelling in the deep for 450 million years. Although deceptively named a horseshoe crab, it is in fact an arthropod, as community science manager at Delaware Center for the Inland Bays, Nivette Perez-Perez, outlines.

Nivette Pérez-Pérez: "Horseshoe crabs, in, in difference of their common name, they're not crabs. They're actually arthropods that are related to spiders and scorpions. This is a female, and one of the ways to see that is this first pair of legs. They're actually pinchers."

Beginning in the 1970s, the biomedical industry's found a special component limulus amebocyte lysate, extracted from their blood, invaluable. Vital for detecting bacterial endotoxins, which can contaminate medications, needles, joint replacements and vaccines, demand for horseshoe crab blood has surged in recent years.

Horseshoe crab advocate Glenn Gauvry's president of the Ecological Research and Development Group.

Glenn Gauvry: "One of the things that has always been tested with this test is vaccines. So we've got vaccines around the world for all kinds of things, but we now have a whole new wave of vaccines being produced and developed for the battle against Covid. And they're being tested on, on the same test made from the horseshoe crab blood."

With somewhere in the region of half a million horseshoe crabs being harvested and bled for this chemical a year, challenges arise. In addition to the 15 percent of these which never recover, wider threats to their existence reinforce the necessity for an effective horseshoe crab blood substitute to be developed. Although Swiss biotech company Lonza's synthesised an effective alternative, recombinant factor C, this compound is yet to receive regulatory approval.

Until then, the horseshoe crab's Delaware spawning grounds will remain under close scrutiny by passionate local volunteers. Delaware Department of Natural Resources education coordinator Laurel Sullivan describes the scene.

Laurel Sullivan: "We have the largest spawning population in the world in the Delaware Bay. So it's something that people in this area take very seriously and they're really passionate about, because it's something that's really unique to this area."

View Less