Anti-ERVK-18 antibodies are used in the immunodetection of the protein endogenous retrovirus group K member 18. In humans, the canonical protein has a reported length of 560 amino acid residues and a mass of 63.7 kDa. Its subcellular localization is in the cell membrane. It is noted to be expressed at higher level in the thymus. It is a member of the Beta type-B retroviral envelope protein family. Post-translational modifications have been described, including protein cleavage.