Propionate promotes MHC class I antigen presentation and anti-tumor immunity.

Propionate enhances MHC class I antigen presentation, stabilizes tumor cell MHC I, and boosts anti-tumor immunity by promoting CD8+ T cell infiltration and activation.

• Why it matters: Defective tumor antigen presentation allows immune evasion and resistance to immune checkpoint blockade, highlighting the need for strategies to improve tumor immunogenicity and therapy response.
• What they did: Researchers identified propionate as a potent enhancer of MHC class I presentation, demonstrating its ability to stabilize MHC I on tumor cells and interact with STUB1 to prevent its degradation, using biochemical and cellular assays.
• The result: Propionate or its producer Akkermansia muciniphila significantly improved anti-PD-1 therapy efficacy, suggesting dietary or probiotic interventions could enhance immune checkpoint treatments.