Bone marrow stromal cell antigen 2 (BST2) (BST2)

Bone marrow stromal cell antigen 2 (BST2), also known as Tetherin or CD317, is a type II transmembrane glycoprotein that serves as a key component of the innate immune system and a significant marker in oncology (UniProt: Q10589). Its primary biological function is acting as a viral restriction factor, where it physically anchors budding enveloped viruses, such as HIV-1 and Ebola, to the host cell membrane to prevent their dissemination (PubMed: 18193035). In addition to its antiviral role, BST2 is involved in cell-to-cell adhesion and the activation of pro-inflammatory signaling pathways like NF-kappaB (PubMed: 23136159). In the context of disease, BST2 is frequently overexpressed in various cancers, including multiple myeloma, breast cancer, and lung cancer, where it promotes tumor growth and metastasis (PubMed: 25605115). This high expression on malignant cells makes it a viable therapeutic target for monoclonal antibodies and bispecific T-cell engagers, such as XmAb24306, which aim to induce targeted immune-mediated destruction of tumor cells (ClinicalTrials.gov: NCT03513939). However, the presence of BST2 on some healthy tissues and the evolution of viral proteins like Vpu to counteract its effects remain important considerations for drug development.

Other names

TetherinCD317HM1.24 antigen

Antibody-dependent cellular cytotoxicity (ADCC), T-cell redirection via bispecific antibodies, and physical restriction of viral budding (PubMed: 18193035, PubMed: 23136159).