EMORY (US)—Lampreys are primitive creatures—basically, tubes with teeth. Yet, researchers have discovered that lampreys have two kinds of immune cells that look very much like B and T cells in mammals, birds, and fish.
Lampreys have a completely different set of tools for fighting infections. They have proteins in their blood that glob on to invaders, but they don’t look anything like the antibodies found in other animals.
Similarly, lampreys have cells that look like T cells, in terms of some of the genes that are turned on. However, they don’t have MHC genes, which are important in human transplant medicine because they determine how and when T cells get excited and reject transplanted organs.
Lampreys are thought to be an early offshoot on the evolutionary tree, before sharks and fish, and way before critters that crawl on land. This suggests that the categories (B or T) came first even though the characteristic features of the cells (antibodies/responding to MHC) are different.
“Lampreys have the same types of cells, but they just use different building blocks to put them together,” Cooper says.
Cooper made pioneering studies defining the role the thymus plays in immune development at the University of Minnesota in the 1960s. The thymus is where T cells develop and where they get their name.
He is now collaborating with Thomas Boehm in Freiburg, Germany to better understand the evolution of the thymus. Lampreys don’t have a thymus, but they may have an area next to their gills where the T-like cells develop.
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