Wednesday, August 17, 2005

Comparative immunology: crocodiles make your immune system look wimpy

Eons ago, when I was a young medical student, I was really interested in comparative immunology and in the evolutionary history of the immune system. I figured there had to be gold in comparing how different organisms evolved different solutions to the pathogen problem. Of course I had a zillion interests, so that one came and went.

It's nice to know that research in comparative immunology has since borne fruit. It turns out crocodiles have one heck of an immune system...
Science News Article |

... The crocodile's immune system is much more powerful than that of humans, preventing life-threatening infections after savage territorial fights which often leave the animals with gaping wounds and missing limbs.

"They tear limbs off each other and despite the fact that they live in this environment with all these microbes, they heal up very rapidly and normally almost always without infection," said U.S. scientist Mark Merchant, who has been taking crocodile blood samples in the Northern Territory.

... "If you take a test tube of HIV and add crocodile serum it will have a greater effect than human serum. It can kill a much greater number of HIV viral organisms," Britton said from Darwin's Crocodylus Park, a tourism park and research center.

Britton said the crocodile immune system worked differently from the human system by directly attacking bacteria immediately an infection occurred in the body.

"The crocodile has an immune system which attaches to bacteria and tears it apart and it explodes. It's like putting a gun to the head of the bacteria and pulling the trigger," he said...
So what's the downside of that sort of immune system? Do crocs get nasty auto-immune disorders? It's odd that this is a press release now; the HIV work was done in 1998. I doubt there will be many practical implications; but this is great basic scienc work.

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