CHARLESTON, S.C. The blood of horseshoe crabs is blue.

The white blood cells from that blue blood can be used to ensure that medical devices and drugs are safe.

Horseshoe crabs are really spiders.

The things you can learn on a tour of biotech and medical manufacturing businesses in and around this Southern coastal town are rather interesting. One of those interesting facts, and not especially well known, is that Charleston has such industries. And it currently is attempting to send this message to the rest of the world.

Besides being a haven of Civil War lore (including Fort Sumter, where it all started), having all sorts of American history on every corner and featuring an array of sunny beaches, Charleston has a strong central core of medical institutions busily working at health care research and development, and a growing number and range of medical manufacturers.

One of these is Endosafe, an enterprise focused on extracting blood from horseshoe crabs and turning the blood into an assay able to detect pyrogenic pathogens that withstand ordinary sterilization in pharmaceuticals and medical devices.

But horseshoe crab is a misnomer, says Foster Jordan, executive director of in vitro detection systems for the company. “They’re not crabs they’re spiders,” he says, holding one of the fascinatingly ugly and writhing creatures in the air. He notes that it’s healthy and then puts it back in a wet bin full of others of its ilk their next stop before being returned to the Atlantic Ocean.

He also notes that this one is male, its shell about half-basketball size, since females normally are three to five times larger another interesting fact.

Endosafe over two months extracts the blood, with lines of crabs in rows on one side of the room, technicians drawing blood from others nearby. This opportunity comes when the creatures crawl onto beaches to spawn, are collected by local fishermen and brought Endosafe’s processing facility. “April and May are dedicated to bleeding,” explains Jordan. “The blood is frozen and the rest of the year we make the finished product.”

At the plant, the crabs are checked for health, washed down and then bled, their blue blood ironically, perhaps, a North Carolina Tarheel kind of blue running into plastic bags. Jordan emphasizes that the bleeding stops short of taking too much of the blue stuff, and the crabs usually are returned to their home habitats within 24 hours.

In June the Endosafe facility changes into a processing plant, the white cells separated from the blood, then frozen and stored until processing into a vial-type kit used by device and drug makers all over the world. Endosafe was founded in 1987 by James Cooper, a nuclear pharmacist at the University of South Carolina in Columbia, who exploited the discovery that the animal’s blood was superior to an older rabbit test for detecting Gram-negative pathogens called pyrogens or endostatins, and developed from that knowledge an FDA-cleared assay.

In 1994, the company was purchased by Charles River Laboratories, of Wilmington, Mass., which specializes in another animal used for medical R&D, primarily mice genetically engineered for use in pharmaceutical research.

Jordan says there’s really no definitive explanation as to why the horseshoe crab’s blood has such a unique property, but supposes that its ocean-bottom habitat has enabled it to engineer a robust immunity. While the company’s main product is essentially a reagent used in testing of drugs and devices (the devices, for instance, are dipped in water laced in the reagent), he notes that Endosafe recently licensed from Germany a new test it rolled out in February. That assay detects endotoxins directly in blood, providing an assay that is more specific and therefore more useful for testing the most complex drugs and biologics. Which test to use depends on the product and the sensitivity required, Jordan notes.

Additionally, he says, Endosafe is continually adding software and instrumentation systems to increase ease of use and sensitivity of its products.

The company’s particular sector of the biotech world is a small one, with just two other competitors Associates of Cape Cod, of Falmouth, Mass., and BioWhittaker, of Walkersville, Md. In this field, Jordan puts Endosafe as No. 1 in the U.S. and “by the end of the year, No. 1 globally,” driven by its expanding product lines.

Among a variety of ties to the Charleston area, Jordan himself is an important one. He was in graduate school in Charleston and decided to join the company early in its history when it was still in development, struggling for its first sales. A major contract from Japan then put it on the path to success.

The company’s main connection to Charleston is most clearly linked to the fact that the Eastern shore from Maine to Florida is one of just two regions on the planet where horseshoe crabs can be found, and South Carolina is the only state that by law limits horseshoe crab harvesting only to medical research. The animal’s only other home is the China Sea, and Endosafe has established a facility there to serve the Chinese market.

Jordan notes that, given modern logistics and communications, Endosafe doesn’t have to remain in Charleston. It could collect the crabs here, do the bleeding and send the frozen product elsewhere for processing.

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