Anti-SPEF2 antibodies are used in the immunodetection of the protein sperm flagellar 2. In humans, the canonical protein has a reported length of 1822 amino acid residues and a mass of 209.8 kDa. Its subcellular localization is in the cell projections, Golgi, and cytoplasm. Up to 4 different isoforms have been reported for this protein. It is notably expressed in the nasopharynx, fallopian tube, and bronchus. SPEF2 is known to be required for correct axoneme development in spermatozoa. The SPEF2 gene has been associated with the disease, Spermatogenic failure. Synonyms for this target antigen include cancer/testis antigen 122, testis tissue sperm-binding protein Li 47a, and sperm flagellar protein 2. SPEF2 gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species. Some SPEF2 antibodies may have been used in research and have associated citations. Immunofluorescence is a widely used application for these antibodies. ELISA and Immunocytochemistry are also common applications.