Any vegetarian who has tried to start eating meat again will tell you: It can be a difficult transition. Zuri Sullivan, a postdoctoral researcher at Harvard, will tell you exactly what is going on in the gut when that happens. In a paper published in March in Science, Sullivan and her colleagues switched laboratory mice to a high-carb or a high-protein diet to see how cells in their guts would respond. Within five days, the mices’ guts had far higher levels of some of the chemicals necessary for digesting carbohydrates.
But even more surprising was another difference. A mysterious and unusual type of immune cell, called gamma delta T cells, showed up while the gut was reconfiguring itself — and seemed to be playing a critical role in the process.
“The idea of being able to become a scientist — and maybe you can make a discovery that either changes many people’s lives or changes how textbooks are written, I was like, ‘Oh, that’s what I want to do.’”
“This was a big deal for a couple of reasons,” Sullivan said. It indicated a potential job for these cells — which is something scientists hadn’t really identified before. But more intriguingly, the presence of these cells also indicated that the immune system was linked to an animal’s nutrition. “It’s hard to say precisely how this works,” she noted. “There’s still a lot of detail that’s all like ongoing work as being kind of teased out.”
Sullivan hopes her career path continues to look at the broader picture of how the immune system works in unexpected ways. Her current work focuses on the relationship between a person’s gut, immune system, and brain.
“I think my sort of vision for my career is to understand how the immune system helps animals adapt to their environment,” she said — whether that environment includes an unwelcome bacteria or virus or an unexpected change to a keto diet.
Indeed, the immune system is what originally sparked Sullivan’s interest in science. After attending a talk in high school about HIV elite controllers, she knew she wanted to go into research. “The idea of being able to become a scientist — and maybe you can make a discovery that either changes many people’s lives or changes how textbooks are written,” she said, “I was like, ‘Oh, that’s what I want to do.’”
— Kate Sheridan