Nav: Home

Research on the fossil

March 13, 2020

Pathogens such as viruses and bacteria have been at war with their hosts for millions of years. The arms race between the immune system of the hosts and infectious pathogens is considered to be a critical driver of evolution. All vertebrates, including humans, developed a very sophisticated self-protection device, which is called the adaptive immune system. Specialized immune cells called T cells and B cells detect and destroy invading pathogens. One of its key features and its secret weapon is immunological memory. The cells remember infections leading to an even more efficient reaction to the same pathogen when re-exposed.

Searching for the design principles of adaptive immunity

In recent years, researchers have found that adaptive immunity has evolved at least twice independently in the early phases of vertebrate evolution. Vertebrates are commonly divided into two groups. Animals of the most numerous group all possess a jaw, and hence are called "jawed" vertebrates; they encompass such diverse creatures as sharks and humans. By contrast, a small group of vertebrates lacks jaws, and hence these animals are called "jawless" vertebrates; lampreys and hagfish belong to this group.

"The basic design of the adaptive immune systems in these two groups of vertebrates are surprisingly similar, considering that these groups evolved independently for more than 500 million years," explains Thomas Boehm, Director at the Max Planck Institute of Immunobiology and Epigenetics. The scientists know that all vertebrates share the two lineages of T and B cells that are equipped with receptors capable of recognizing foreign structures, often referred to as antigens. Because the immune system has to distinguish between very different types of antigens, the structures of the receptors also vary; they are made up of similar but not identical building blocks that are produced in a random fashion during the development of T and B cells.

Dissecting adaptive immunity with CRISPR/Cas9

One of the big surprises of recent research was that the building blocks of antigen receptors of jawless and jawed vertebrates are structurally different, yet serve the same purpose during immune defence. "Lampreys use short peptides, called leucine-rich repeats and arrange them like strings on a bead to form the so-called variable lymphocyte receptors. However, up to now, it was unclear how these strings are stitched together," explains Ryo Morimoto first-author of the study. This important question has now been answered by the Max Planck researchers in Freiburg, working together with scientists at the French INRA in Rennes.

To do this, the scientists succeeded for the first time in using the famous gene scissor CRISPR/Cas9 to study gene function in the immune system of lampreys. By using CRISPR/Cas9, they specifically destroyed a gene in lampreys that they long suspected to be required for the assembly of a particular class of variable lymphocyte receptor genes, which contain the blueprint of lamprey antibodies. Indeed, when the so-called cytidine deaminase gene 2 (CDA2) was crippled, the lamprey could no longer produce antibodies.

Shared tool-kit to create antibodies

The CDA2 gene is of great interest to immunologists, because it is related to a gene, called AID, of jawed vertebrates that helps to refine the specificity of their antibodies. "It seems, that nature has chosen molecules from a shared tool-kit to support the formation of useful antibodies in both types of vertebrates. These results are an important advance in our understanding of the evolution and function of the immune system of vertebrates," says Thomas Boehm. Now that the scientists have successfully used gene scissors to investigate immune gene function in lampreys, they plan to test the role of many other genes that are suspected of supporting immune functions in these ancient vertebrates.

By collecting more information using this genetic approach, they hope to eventually reconstruct the key components of the immune system of the first-ever vertebrate. Doing this will allow them to learn which of the many functions that are now carried out by the immune system of living vertebrates are absolutely essential and which can be dispensed with. Ultimately, the Max Planck researchers hope to use this information to better understand the consequences of failing immune protection in human patients suffering from autoimmune diseases and cancers.
-end-


Max Planck Institute of Immunobiology and Epigenetics

Related Immune System Articles:

Too much salt weakens the immune system
A high-salt diet is not only bad for one's blood pressure, but also for the immune system.
Parkinson's and the immune system
Mutations in the Parkin gene are a common cause of hereditary forms of Parkinson's disease.
How an immune system regulator shifts the balance of immune cells
Researchers have provided new insight on the role of cyclic AMP (cAMP) in regulating the immune response.
Immune system upgrade
Theoretically, our immune system could detect and kill cancer cells.
Using the immune system as a defence against cancer
Research published today in the British Journal of Cancer has found that a naturally occurring molecule and a component of the immune system that can successfully target and kill cancer cells, can also encourage immunity against cancer resurgence.
First impressions go a long way in the immune system
An algorithm that predicts the immune response to a pathogen could lead to early diagnosis for such diseases as tuberculosis
Filming how our immune system kill bacteria
To kill bacteria in the blood, our immune system relies on nanomachines that can open deadly holes in their targets.
Putting the break on our immune system's response
Researchers have discovered how a tiny molecule known as miR-132 acts as a 'handbrake' on our immune system -- helping us fight infection.
Decoding the human immune system
For the first time ever, researchers are comprehensively sequencing the human immune system, which is billions of times larger than the human genome.
Masterswitch discovered in body's immune system
Scientists have discovered a critical part of the body's immune system with potentially major implications for the treatment of some of the most devastating diseases affecting humans.
More Immune System News and Immune System Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Clint Smith
The killing of George Floyd by a police officer has sparked massive protests nationwide. This hour, writer and scholar Clint Smith reflects on this moment, through conversation, letters, and poetry.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.