CD276 antigen (B7 homolog 3 protein) (CD276 (B7-H3))

CD276 antigen (B7 homolog 3 protein), abbreviated as CD276 or B7-H3, is a type I transmembrane protein belonging to the B7 family of immune checkpoint molecules. It is expressed at the mRNA level in most tissues, but post-transcriptional regulation restricts surface expression in normal tissues while enabling high expression in many cancers, especially in the predominant 4Ig-B7-H3 isoform in humans[1][2][3][4]. B7-H3 serves as an immune checkpoint with dual roles: costimulatory or coinhibitory activity for T cells, but primarily, it acts to suppress T cell activation, proliferation, and anti-tumor immune responses in malignancy[1][2][3][4][5]. In addition to immune regulation, B7-H3 promotes tumor progression by enhancing cell migration, invasion, angiogenesis, chemoresistance, epithelial-to-mesenchymal transition, and altering tumor cell metabolism (notably glycolysis)[2][7]. B7-H3 is an attractive target for antibody therapies, antibody-drug conjugates, and CAR T cells due to its high, disease-associated expression in solid and hematologic tumors. Drugs targeting B7-H3, such as enoblituzumab and experimental CAR T therapies, are in clinical and preclinical development[1][2][3]. Expression of B7-H3 may serve as a biomarker for patient selection and as a prognostic marker in diseases like acute myeloid leukemia[3]. Safety concerns include low-level expression in some normal tissues and incomplete understanding of normal physiological functions, warranting careful clinical monitoring[1][2].

Other names

B7-H3B7 homolog 3CD276B7H3B7RP-2

Immune checkpoint inhibition (antibody or CAR T cell blockade of B7-H3 suppresses its immune-inhibitory function); Direct tumor cell killing via antibody-dependent or CAR-mediated cell cytotoxicity; Inhibition of tumor-promoting signaling pathways