A strong immune response relies on the capacity to detect infections and changes in cells. In humans, there exists a specific molecule on cell surfaces known as MR1. This molecule plays a role in sensing certain small metabolites that come from both cellular and microbial origins; however, the full range of what MR1 can detect is still uncertain.
A recent study published in PNAS by researchers at the Monash University Biomedicine Discovery Institute has revealed that a form of Vitamin B6 attached to MR1 can activate immune cells that respond to tumors. This research was part of an international collaboration led in part by scientists from the University of Melbourne.
Dr. Illing stated, “Our results indicate that Vitamin B6 molecules presented by MR1 offer a way for the immune system to identify changes in cellular metabolism or metabolite levels, which could help differentiate cancer cells,” she explained.
“Finding small molecules or metabolites capable of activating immune cells with cancer-fighting potential is a crucial step in understanding the role that metabolite sensing plays in anti-cancer immunity.”
This study focused on using unbiased mass spectrometry to analyze small molecules attached to MR1, determining the structural details of how MR1 interacts with Vitamin B6, and performing immunological tests led by Dr. Mitchell McInerney and Dr. Wael Awad from the Monash Biomedicine Discovery Institute, as well as Dr. Michael Souter and Mr. Yang Kang from the University of Melbourne, Peter Doherty Institute.
Although it’s not yet known if Vitamin B6 can be used in treatments, Dr. Illing pointed out, “Gaining insight into the extensive role of MR1 in immunity could reveal new pathways for therapeutic strategies.”
A noteworthy aspect of this discovery is that MR1 differs minimally among individuals, with very few genetic variants present in the human population. “Thus, understanding immune activation through MR1 may lead to therapeutic strategies that are widely applicable,” Dr. Illing added.
She also mentioned that future research will determine if Vitamin B6 and similar molecules are presented by MR1 on cancer cells at different levels compared to healthy cells, which would allow for targeted cancer therapies, or whether other small molecules shown by MR1 can aid in distinguishing between cancerous and healthy cells.