5-OP-RU

5-OP-RU (5-(2-oxopropylideneamino)-6-D-ribitylaminouracil) is a potent, microbial-derived small molecule ligand that serves as the primary antigen for Mucosal-Associated Invariant T (MAIT) cells. It is a pyrimidine intermediate formed during the bacterial riboflavin biosynthesis pathway through the non-enzymatic reaction of 5-amino-6-D-ribitylaminouracil (5-A-RU) with small glyoxals like methylglyoxal. 5-OP-RU is captured by the MHC class I-related protein 1 (MR1) within antigen-presenting cells and presented on the cell surface. The MR1-5-OP-RU complex is specifically recognized by the semi-invariant T-cell receptor (TCR) of MAIT cells, triggering their activation, proliferation, and production of pro-inflammatory cytokines (such as IFN-gamma and TNF) and cytotoxic granzymes. While currently utilized primarily as a research reagent to study innate-like T-cell responses and MR1-restricted immunity, 5-OP-RU is being investigated as a potential mucosal vaccine adjuvant and in cancer immunotherapy strategies to harness MAIT cell-mediated anti-tumor activity, including in the context of acute myeloid leukemia (AML).

Other names

5-(2-oxopropylideneamino)-6-D-ribitylaminouracil