Indoleamine 2,3-dioxygenase 1 (IDO1) (IDO1)

Indoleamine 2,3-dioxygenase 1 (IDO1) is a cytosolic enzyme that catabolizes tryptophan to kynurenine, overexpressed in tumor cells and antigen-presenting cells, promoting immunosuppression by inhibiting T-cell proliferation and activating regulatory T cells. "IDO long peptide antigens" refers to synthetic long peptides (e.g., 21 amino acids) derived from IDO1, used in therapeutic cancer vaccines like IO102 to elicit CD4+ and CD8+ T-cell responses targeting IDO1-expressing cells in the tumor microenvironment, enhancing antitumor effects often in combination with checkpoint inhibitors. These peptides are processed by dendritic cells for MHC class I/II presentation, breaking tolerance to IDO1 and countering its immunosuppressive role, with activity against IDO1+ tumors and non-IDO1 tumors via immune modulation.

Other names

IDOindoleamine-pyrrole 2,3-dioxygenase

Activates T cells against IDO1-expressing cells, induces CTL-mediated killing of IDO1+ tumor cells and immune cells, enhances antitumor immunity via CD8+ and CD4+ T-cell responses, synergizes with anti-PD1/PD-L1 therapies