Scientists decipher how T cells hunt down infection

It turns out that T cells, which help fight infection, are similar to animals like spider monkeys, tuna and sharks in how they "hunt" their prey. They use lots of short-distance movements and the rare longer one to zero in on attacking a target infection, a group of researchers from the University of Pennsylvania, Massachusetts General Hospital and elsewhere have found.

And knowing how these crucial immune cells move could open the door to new ways of treating diseases like cancer, the scientists argue. That kind of treatment could be years away, but understanding the pattern T cells use to stalk and attack their prey is a first step toward eventually finding new ways to enhance how T cells do their jobs. By knowing what makes those T cells move, the finding could open the door to a drug or vaccine that helps boost that activity, making them more effective in finding the disease and attacking it, the researchers say. It is definitely a thesis that's worth more attention.

"You might be able to devise strategies to make the T cells more efficient at finding those cells," Christopher Hunter, chair of the pathobiology department in the University of Pennsylvania School of Veterinary Medicine and the paper's senior author, said in a statement.

To do their work, they studied mice infected with the parasite Toxoplasma gondii, a common infection that strikes both humans and animals and can lie dormant in the brain, the researchers note. (People with compromised immune systems, however, can die from the infection.) Multiphoton imaging helped the scientists follow the movement patterns of individual T cells in the mice's living tissue. They saw lots of quick movements and a few longer ones, similar to how certain predators look for their prey in the animal kingdom, indicating that T cells "look" for their infection target before hitting it. (This model is known as a Lévy walk.)

And how fast do those T cells move? It seems that the chemokine CXCL10 and its receptor play a role, reinforcing existing belief that chemokines influence how immune cells move. The team found that CXCL10 appeared in large numbers in the mice with infections. Blocking CXCL10 reduced the T cell number and led to much more parasites. Next, the researchers say they will work to track the movement of other cell types. Further study details will be published in the journal Nature.

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