Anti-LY9 antibodies are used in the immunodetection of the protein lymphocyte antigen 9. In humans, the canonical protein has a reported length of 655 amino acid residues and a mass of 72.1 kDa. Its subcellular localization is in the cell membrane. Up to 4 different isoforms have been reported for this protein. It is notably expressed in the tonsil, testis, spleen, and appendix. LY9 is reported to be a self-ligand receptor of the signaling lymphocytic activation molecule (SLAM) family. Post-translational modifications have been described, including glycosylation. Ly9 is also used as a cellular marker for characterizing hematopoietic stem cells. Synonyms for this target antigen include SLAMF3, hly9, mLY9, T-lymphocyte surface antigen Ly-9, SLAM family member 3, and CD229. LY9 gene orthologs have been reported in the mouse, rat, bovine and chimpanzee species. Over 110 citations in the literature describe the use of Ly9 antibodies in research. Flow Cytometry is a widely used application for these antibodies. In addition, Western Blot is also a common application.