BTN3A3 is a butyrophilin family member that functions as a membrane protein with dual roles in immune regulation and tumor suppression. Primarily, BTN3A3 participates in γδ T cell activation through heteromerization with BTN3A1 and BTN2A1 to form phosphoantigen-induced receptor complexes that trigger γδ TCR signaling 1. The protein is transcriptionally regulated by NLRC5, a transcriptional regulator of MHC class I genes, linking it to non-conventional T cell responses against metabolically abnormal cells 2. Beyond immunity, BTN3A3 exhibits antiviral properties specifically against avian influenza viruses by inhibiting viral RNA replication at early infection stages, with viral evasion determined by specific nucleoprotein residues 3. In cancer biology, BTN3A3 functions as a tumor suppressor in clear cell renal cell carcinoma, suppressing proliferation and migration through RPS3A interaction and ROS/MAPK pathway modulation 4. Clinically, BTN3A3 variants are implicated in generalized pustular psoriasis (GPP), an autoinflammatory keratinization disease, where loss of function activates NF-κB signaling and IL-36 inflammatory axis disruption 56. BTN3A3 is also identified as a potential drug target for psychiatric disorders including schizophrenia and bipolar disorder 7, and as a therapeutic target for chr6 kidney disease progression 8.