Anti-B15 antibodies enable researchers to detect and measure the B15 antigen in biological samples. This target is a reported synonym of the NDUFB4 gene, which encodes NADH:ubiquinone oxidoreductase subunit B4. This protein is known to function in the response to oxidative stress, among other biological roles. The human version of B15 has a canonical amino acid length of 129 residues and a protein mass of 15.2 kilodaltons, although 2 isoforms have been identified. It is reported to be localized in the mitochondria of cells and widely expressed in many tissue types. This target antigen may also be known as CI-B15.