Vitamin B6 Boosts Tumor-Immune Response

Effective immunity is dependent on the ability to detect infection and undergo cellular change. In humans, there is a particular molecule on the surface of cells called MR1 which is boosted by Vitamin B6. MR1 detects various small molecule metabolites produced from cellular and microbial sources; nevertheless, the scope of metabolite sensing is unknown.

Monash University Biomedicine Discovery Institute researchers discovered a type of vitamin B6 linked to MR1 that can engage tumor-reactive immune cells, according to a study published in PNAS. The investigation was carried out by an international collaborative team co-led by University of Melbourne researchers.

According to Dr. Illing, “Our findings suggest that vitamin B6 molecules displayed by MR1 represent a means for the immune system to detect altered cellular metabolism/metabolite levels, that may distinguish cancer cells,” she said.

“Identification of small molecules/metabolites able to activate immune cells with cancer reactivity is a key step in understanding how small molecule sensing might contribute to anti-cancer immunity.”

The unbiased mass spectrometry analysis of small molecules bound to MR1, the structural resolution of the interactions between MR1 and vitamin B6, and immunological assays performed by lead authors Dr. Mitchell McInerney and Dr. Wael Awad at Monash Biomedicine Discovery Institute, as well as Dr. Michael Souter and Mr. Yang Kang at the University of Melbourne’s Peter Doherty Institute, were critical to this study.

While it’s not yet clear if the vitamin B6 molecule can be utilized in therapeutics, “understanding the breadth of MR1 mediated immunity has the capacity to illuminate routes for therapeutic intervention,” Dr. Illing said.

An important aspect of the finding is that MR1 differs very little across individuals—with few known genetic variants in the human population. “Thus, understanding immune activation mediated via MR1 may pave the way for therapeutic interventions with broad utility,” Dr. Illing said.

She added that the next steps in research will determine whether vitamin B6 and related molecules are displayed at altered levels by cancer cells’ MR1 compared to healthy body cells, allowing for specific cancer targeting, or if other small molecules displayed by MR1 may help differentiate cancerous from healthy cells.

More information: Mitchell P. McInerney et al, MR1 presents vitamin B6–related compounds for recognition by MR1-reactive T cells, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2414792121