Ivaylo Ivanov, an immunologist at Columbia University who studies the role of intestinal bacteria in the body’s immune response, in collaboration with Caltech researcher Pamela Bjorkman, has received a two-year, $200,000 Innovation Fund award from the Pew Charitable Trusts. The grant will fund Ivanov’s ongoing research with Bjorkman.
The researchers will study how the commensal bacteria that live in our bodies and make up our microbiome interact with cells in the small intestine through an unusual mechanism. While pathogenic microbes are known to destroy cells and cause disease, relatively little is known about our own commensal microbes and their positive role on health. In a 2009 study in Cell, Ivanov, then a postdoctoral researcher at NYU, showed that a type of common microbe, segmented filamentous bacteria, could trigger the formation of specialized immune cells in the small intestine of mice and protect the mice from infection. The idea that bacteria in our microbiome could fight disease was new, and since then interest in the trillions of microbes that inhabit the human gut has exploded.
Immune cells are activated when the pod-shaped commensal microbe burrows into the gut's outer epithelial cells. The new study examines how the bacteria transfers proteins inside the host. Image courtesy of Ivanov.
At Columbia, Ivanov has continued to study the role of beneficial bacteria in regulating the immune system. He and his colleagues discovered that resident gut microbes produce special proteins that activate immune cells, and that these proteins are taken inside cells in the gut through an unusual mechanism. Using microscopic imaging technology developed in Bjorkman’s lab at Caltech, he and Bjorkman have found that intestinal cells ingest pieces of bacteria in tiny membrane vesicles. This type of cell-microbe interaction has never been seen before, he said.
Under their Pew collaboration, Ivanov and Bjorkman will study this process further and see if something similar happens in the human gut. Both former Pew scholars, Ivanov and Bjorkman began working together in 2015, and are one of six pairs of researchers to receive the inaugural Pew Innovation Fund award.