Thomsen-nouveau antigen (Tn antigen) (Tn antigen)

The Thomsen-nouveau antigen, commonly known as the Tn antigen, is a truncated O-glycan consisting of a single N-acetylgalactosamine (GalNAc) residue alpha-linked to a serine or threonine residue on proteins (Springer, 1984; Ju et al., 2011). It is a well-characterized tumor-associated carbohydrate antigen (TACA) that arises from incomplete O-glycosylation, often due to mutations or downregulation of the molecular chaperone Cosmc or the enzyme T-synthase (Ju et al., 2011). While virtually absent in healthy adult tissues, the Tn antigen is overexpressed in a wide variety of epithelial cancers, including breast, colon, and prostate malignancies, where it correlates with poor prognosis and metastasis (Springer, 1984; Posey et al., 2016). Its high tumor specificity makes it an attractive target for various immunotherapeutic strategies, including monoclonal antibodies, glycopeptide-based vaccines like MAG-Tn3, and chimeric antigen receptor (CAR) T-cell therapies (Posey et al., 2016; Lo-Man et al., 2004). These treatments aim to exploit the unique glycan structure to selectively destroy malignant cells while sparing normal tissue (Posey et al., 2016). Research continues to focus on overcoming the low immunogenicity of carbohydrate structures to enhance the efficacy of Tn-targeted therapies (Lo-Man et al., 2004).

Other names

Tn antigenCD175GalNAc-alpha-Ser/ThrN-acetylgalactosamine-alpha-O-serine/threonine

Targeting the Thomsen-nouveau antigen typically involves immunotherapy approaches such as monoclonal antibodies that induce antibody-dependent cellular cytotoxicity (ADCC), cancer vaccines designed to elicit a humoral and cellular immune response against Tn-expressing cells, or CAR-T cell therapies engineered to recognize and eliminate cells presenting the Tn glycan on surface proteins like MUC1 (Posey et al., 2016; Lo-Man et al., 2004).