THE LAMPREY, a primitive jawless fish, turns out to have an immune system found nowhere else in nature.
To defend against an ever-changing array of invaders, some of the blood cells of backboned animals rearrange their DNA to generate a huge diversity of proteins, and then select the ones that target a particular pathogen. This process is known as adaptive immunity.
The defence proteins, such as antibodies, are built from a large array of immunoglobin building blocks in all vertebrates. But immunoglobin genes have never been found in the lamprey and its close relative the hagfish. Now Zeev Pancer鈥檚 team from the University of Alabama at Birmingham has shown that the lamprey鈥檚 adaptive immune system is based on a completely different type of genetic building block, called leucine-rich repeats (Nature, vol 430, p 174). 鈥淭his should open people鈥檚 minds about immune evolution,鈥� says Pancer. There could be more revelations awaiting discovery in other animals, he adds.
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