THE horseshoe crab is one of the many sea creatures that can be found in our coastal waters.
While its eggs are used in delicacies, is it true that its blood is used in making vaccines?
Verdict:
TRUE
The horseshoe crab, a creature that is said to be around for over 450 million years, has bright blue blood.
The blue comes from the metal used by the protein in their blood cells to help it transport oxygen.
All vertebrates have a protein in their blood called haemoglobin that uses iron, whereas the protein in horseshoe crab blood (haemocyanin) uses copper.
Aside from haemocyanin, their blue blood is rich in immune cells that are exceptionally sensitive to toxic bacteria.
When these immune cells meet invading bacteria, they clot around it and protect the rest of the horseshoe crab's body from toxins.
Scientists used these blood cells to develop a test called Limulus Amebocyte Lysate (LAL) which checks new vaccines for contamination.
This technique has been used all over the world since the 1970s to stop medical professionals from giving out jabs full of bad bacteria that could make patients very ill.
LAL is also used in testing against a type of bacteria that can contaminate medications, needles and devices like hip replacements.
It is reported that every year, around 500,000 horseshoe crabs are harvested and bled for LAL. It is estimated that the death rate of the process is about 15%, with survivors released back to sea.
With supply being finite, a gallon (about 3.7 litres) of blood can cost about USD60,000 (RM268,530).
This blue blood is also vital with the emergence of the Covid-19 pandemic in early 2020, with scientists and researchers rushing to look for a vaccine for the coronavirus.
And fast-forward today, it played a role in the various vaccines made available to the public to protect themselves from Covid-19.
Unfortunately, with many LAL manufacturers bleeding hundreds of thousands of horseshoe crabs, the creature is classified as "endangered" in Asia, and "vulnerable" in the US.
While the death rate of bled horseshoes is technically low, the act of being bled impacts the species ability to reproduce.
According to a study done in 2013, bled female horseshoes became sluggish and were less likely to come to shore to breed.
There is some hope for our almost half billion year old friends, a researcher in Singapore successfully produced an enzyme in yeast that pretty much mimics the abilities of LAL she dubbed Factor C. She has already licensed the process to Lonza Group, a Swiss pharmaceutical multinational, who has brought it to the market as a product called PyroGene. A German company named Hyglos has been working on another synthetic endotoxin detector.
These developments bode well for our little horseshoe crabs, as it should decrease the pressure they are under and help rebuild their numbers.
So, the next time you see a horseshoe crab on the beach, remember that it has contributed to keeping you healthy and safe.
References:
1. https://www.nationalgeographic.com/animals/article/covid-vaccine-needs-horseshoe-crab-blood
2. https://www.nhm.ac.uk/discover/horseshoe-crab-blood-miracle-vaccine-ingredient.html
4. https://www.journals.uchicago.edu/doi/pdfplus/10.1086/BBLv225n3p137
5. https://www.horseshoecrab.org/research/sites/default/files/TIBTECH-rFC.pdf
6. https://www.europeanpharmaceuticalreview.com/content_hub/62082/hyglos-gmbh/
