Most lampreys look exactly like something out of your worst nightmare: a snake-like fish, with rings of sharp teeth, and a circular mouth to form a suction over whatever it’s biting into. Hitchcock couldn’t make them up.
Emma Quinlan is a PhD student at MUN’s Faculty of Medicine, and her research has led her to study these strange creatures because their physiology is as unique as their appearance, and could teach us something about how our immune systems work.
Lampreys have an immune system completely unlike anything observed in humans, mammals, birds, or even other fish. Our own “adaptive immune system” is characterized by its ability to “remember” past infections, so that future attacks from the same virus or bacteria can be countered more efficiently.
The lamprey does not have the same types of adaptive immune cells and molecules we have (like antibodies), but their immune system does have the ability to remember past infections. It turns out the common link between our immune system and theirs is something called “AID.”
AID is an enzyme known as activation induced cytidine deaminase. She describes enzymes as “tiny machines that do all the work in our bodies, such as digesting our food or fighting an infection.” AID, which she studies, is an enzyme that prepares the immune system to fight the countless dirt, bugs, bacteria, fungus, and viruses we inevitably encounter every day as we breathe, eat, and touch things.
“Our immune system needs a way to recognize each potential threat, and that is where AID comes in,” she says. “It helps our immune cells recognize each new threat as we encounter it. When AID does not work properly, we can become susceptible to all sorts of diseases, including cancer, so it is vital that we fully understand this enzyme in order to help people who suffer from these conditions.”
For example, “Hyper IgM syndrome 2 (HIGM2),” is a genetic disorder that is caused by defective or deficient AID. Further study of AID could result in gene therapies that can help HIGM2 patients regain AID functionality, thus enabling their immune system to work properly.
Science understands what AID does, but not how it does what it does. And that’s what Quinlan’s research is trying to figure out, in part by better understanding how AID works in lampreys.
“Their unique immune system, so different to our own, yet similar in function, poses unique questions to the scientific community: why did lampreys evolve this type of adaptive immune system and other fish, sharks, birds, mammals, etc evolve another type? What role does AID play in this unique immune system?”
If she can unlock the mysteries of AID, we’d have a better understanding of our own immune systems, which could not only cure various human immune diseases, but certain cancers as well.
For example, an overactive AID enzyme could mutate DNA such as genes that control the life cycles of cells in our bodies. If AID damages these genes, the affected cells could become cancerous. Cancers attributed to AID include B cell lymphomas and certain breast cancers. “If we learn how AID activity is regulated,” she says, “we can learn to ameliorate and possibly prevent these cancers.”