Anti-SPA17 antibodies are used in the immunodetection of the protein sperm autoantigenic protein 17. In humans, the canonical protein has a reported length of 151 amino acid residues and a mass of 17.4 kDa. Its subcellular localization is in the membrane. Among its functions, SPA17 is involved with spermatogenesis. Synonyms for this target antigen include SP17, SP17-1, sperm surface protein Sp17, cancer/testis antigen 22, sperm protein 17, and CT22.