The eel-like sea lamprey may not have as primitive an immune system as many scientists thought. In this week's issue of Nature, researchers report that the lamprey has two distinct classes of immune cells, with similar properties to the T and B cells at the heart of the so-called adaptive immune response in people. T and B cells are found only in jawed vertebrates such as humans, where they protect against harmful bacteria and other invaders. Yet, the lamprey is a jawless vertebrate and seems to have evolved its own defense strategies. Immunologists say the find could shed light on how the human immune system evolved in the first place.
Read the full story on Science's evolution blog, Origins.