Ancient Jawless Vertebrates Used Novel Immune Responses

Dec 22, 2005
Ancient Jawless Vertebrates Used Novel Immune Responses
Image: The sea lamprey is a modern representative of the ancient jawless vertebrates. Researchers at UMBI´s Center of Marine Biotechnology are studying the lamprey to better understand the immune system of humans and other jawed vertebrates. Credit: Ulrike Klenke and Zeev Pancer, Center of Marine Biotechnology, UMBI, Baltimore, Md.

Researchers recently discovered that the sea lamprey, a modern representative of ancient jawless vertebrates, fights invading pathogens by generating up to 100 trillion unique receptors. These receptors, referred to as VLRs, are proteins and function like antibodies and T-cell receptors, sentinels of the immune system in all jawed vertebrates, including humans.

The results, reported in the Dec. 23 Science by Zeev Pancer at the University of Maryland Biotechnology Institute's Center of Marine Biotechnology in Baltimore, and his colleagues, proved ancient vertebrates--both jawed and jawless--used more than one strategy to develop an immune system that would recognize and defend against their myriad bodily invaders.

They studied a type of immune defense mechanism called "adaptive," because as the name implies, it adapts to the incredible number of pathogens in the environment by producing 100 trillion potentially different receptor proteins in order to recognize at least one of the invader's molecules. Recognition of the pathogen is a first step in mounting a defensive response against it.

Some 450 million years ago, both jawed and jawless vertebrates began relying on cells called lymphocytes to support the burgeoning adaptive immune system. But within the lymphocytes from the two types of animals, very different mechanisms evolved to reach very similar ends. Comparing the two immune systems is the basis of Pancer's research.

As in jawed vertebrate immune systems, he found, the diversity of the VLR proteins occurs when thousands of genetic modules go through multiple rounds of random mixing, insertion and deletion. Each new VLR gene functions as a blueprint for the corresponding VLR protein. Thus, through a mixture of chance and necessity, both jawed and jawless vertebrates stay ahead of the pathogens in their ever-evolving battle.

To test the adaptability of this alternative immune mechanism, the researchers immunized lampreys with the anthrax-causing bacterium, a pathogen not normally encountered by fish of any type. Within four weeks, the lamprey immune system had recognized the spores as foreign and responded by producing anthrax-specific VLR proteins that circulated throughout its body.

"By understanding the development and role of the lamprey immune system we can learn about our own immune system and how it functions," said Pancer. "Comparing these two systems is an unparalleled way to look at a basic biological process and also may hold promise for novel diagnostic tools."

Pancer credits the National Science Foundation, which supported this work, as enabling new discoveries that have the potential to unravel such mysteries of biology.

Source: NSF

Explore further: No silver bullet: Study identifies risk factors of youth charged with murder

add to favorites email to friend print save as pdf

Related Stories

Nokia turnaround since handset unit sale continues

2 hours ago

Nokia appears to have turned around its fortunes after the sale of its ailing cellphone unit to Microsoft, reporting a third-quarter net profit of 747 million euros ($950 million), from a loss of 91 million euros a year earlier. ...

Yahoo CEO defends strategy in face of criticism

2 hours ago

Signaling her reign has reached a pivotal juncture, Yahoo CEO Marissa Mayer is trying to convince restless shareholders that the long-struggling Internet company is heading in the right direction.

Recommended for you

World population likely to peak by 2070

3 hours ago

World population will likely peak at around 9.4 billion around 2070 and then decline to around 9 billion by 2100, according to new population projections from IIASA researchers, published in a new book, World Population and ...

Bullying in schools is still prevalent, national report says

4 hours ago

Despite a dramatic increase in public awareness and anti-bullying legislation nationwide, the prevalence of bullying is still one of the most pressing issues facing our nation's youth, according to a report by researchers ...

User comments : 0