Anti-CD229 antibodies enable researchers to detect and measure the CD229 antigen in biological samples. This target is a reported synonym of the LY9 gene, which encodes lymphocyte antigen 9. This protein is known to function in cell adhesion and innate immune responses, among other biological roles. The human version of CD229 has a canonical amino acid length of 655 residues and a protein mass of 72.1 kilodaltons, although 4 isoforms have been identified. It is reported to be localized in the cell membrane of cells and notably expressed in the tonsil, testis, spleen, and appendix. Other names for this target antigen include SLAMF3 and hly9.