CD317. also known as Tetherin or BST-2 (bone marrow stromal antigen 2), is a transmembrane protein encoded by the *BST2* gene. It plays a critical role in innate immunity by restricting the release of enveloped viruses, including HIV-1. Ebola, and SARS-CoV-2. through its unique ability to physically "tether" budding virions to the host cell membrane. Structurally, CD317 features an N-terminal cytoplasmic domain, a transmembrane region, and a C-terminal glycosylphosphatidylinositol (GPI) anchor, enabling it to form parallel dimers that crosslink viral and cellular membranes.
Antibodies targeting CD317 are essential tools for studying its antiviral mechanisms, expression patterns, and interactions with viral proteins (e.g., HIV-1 Vpu, which counteracts CD317 by promoting its degradation). These antibodies are widely used in techniques like flow cytometry, Western blotting, and immunohistochemistry to investigate CD317's role in viral restriction, immune signaling, and cancer biology. Notably, CD317 is overexpressed in certain cancers, such as multiple myeloma, and its antibodies aid in exploring its dual role as both a tumor suppressor and promoter. Research also focuses on CD317's involvement in cell adhesion, NF-κB signaling, and its potential as a therapeutic target. However, its complex regulation and context-dependent functions necessitate careful interpretation of antibody-based assays. Overall, CD317 antibodies remain pivotal in deciphering the interplay between host defense, viral evasion, and disease progression.