These PD-1 ELISA kits are immunodetection tools for measuring the levels of PD-1 in biological samples. PD-1 is an alias name of the human SPATA2 gene, which encodes the protein, spermatogenesis associated 2. Notably, PD-1 is known to play a role in spermatogenesis, among other functions. The SPATA2 protein is described to be 520 amino acid residues in length and 58.4 kilodaltons in mass. It is localized to the nucleus and cytoplasm of the cell. Other names for this target antigen include .