Anti-Btn3 antibodies enable researchers to detect and measure the Btn3 antigen in biological samples. This target is a reported synonym of the BTNL9 gene, which encodes butyrophilin like 9. The human version of Btn3 has a canonical amino acid length of 535 residues and a protein mass of 59.7 kilodaltons, although 3 isoforms have been identified. It is reported to be localized in the membrane of cells. Btn3 is a member of the BTN/MOG protein family.