Anti-PD-1H antibodies enable researchers to detect and measure the PD-1H antigen in biological samples. This target is a reported synonym of the VSIR gene, which encodes V-set immunoregulatory receptor. This protein is known to function in the regulation of cell migration, among other biological roles. The human version of PD-1H has a canonical amino acid length of 311 residues and a protein mass of 33.9 kilodaltons. It is reported to be localized in the cell membrane of cells.