In a recent study published in Nature Communications, Mayo Clinic scientists identify a type of cell that coordinates the immune response within the brain. For researchers looking for ways to treat brain tumors like glioblastoma, this information could support the development of new cancer vaccines and therapies.
"Understanding the immune system in the brain is decades behind other organs," says first author Courtney Malo, a graduate student at Mayo Clinic Graduate School of Biomedical Sciences. "This is mostly because people didn’t think the brain had anything to do with the immune system for a very long time."
In the new study, Malo and her team clarify the fundamentals of how the immune system works in the brain to ultimately help treat neurological diseases ranging from viral infections to cancer. They started by focusing on two types of immune system cells. The first, dendritic cells, ingest the molecules around them and display bits of what they consume, called antigens, on their surface. When the antigen is from an invader, the dendritic cells use it to send out an alert to the immune system. The second cell type is the macrophage. These cells show up to fight infection or consume dead or damaged cells. They engulf an invader and destroy it.
"We used a technique to disable dendritic cells and macrophages from being able to coordinate an immune response in the brains of mice," says Malo. "Then we looked to see if we if we could detect an immune response in the brain."
The team found that both cells are capable of starting an immune response in the brain. But they were surprised to find that the roles of the cells did not overlap.
"We found that one cell type, the dendritic cell, is the key coordinator of immune responses to brain cancer," explains study senior author Aaron Johnson, Ph.D., a Mayo immunologist.
"Our immunotherapy only prevented the tumor from growing when the dendritic cell was able to coordinate an immune response. This makes the dendritic cell type a great target for glioblastoma therapies."
The team hopes that this research will support future studies in the field of cancer immunotherapy.
"Therapies that help the immune system target tumors [immunotherapies] have become widely known in the last few years," says Malo. "And their successes in melanoma and lung cancer have led to a push to using immunotherapies in other cancers, like glioblastoma."