Butyrophilin subfamily 3 member A1 (BTN3A1) is also known as CD277 and BTF5, which belongs to the immunoglobulin superfamily and contains one B30.2/SPRY domain and two Ig-like V-type (immunoglobulin-like) domains. BTN3A1 plays a role in T-cell activation and in the adaptive immune response. Also, BTN3A1 regulates the proliferation of activated T-cells and the release of cytokines and IFNG by activated T-cells. Furthermore, BTN3A1 mediates the response of T-cells toward infected and transformed cells that are characterized by high levels of phosphorylated metabolites, such as isopentenyl pyrophosphate.