Anti-inhibitor of Bruton tyrosine kinase antibodies are used for the immunodetection of the protein encoded by the IBTK gene. In humans, the canonical protein has a reported length of 1353 amino acid residues and a mass of 150.5 kDa. Its subcellular localization is in the membrane and cytoplasm. Alternative splicing is reported to yield 3 different isoforms for this protein. It is reported to be expressed in DeFew, HEK293T, HeLa and in Jurkat, MC3 and NB4 lymphoid cells. It is known to act as a inhibitor of BTK tyrosine kinase activity, thereby playing a role in B-cell development. Other names for this target antigen include BTKI, BTK-binding protein, Bruton agammaglobulinemia tyrosine kinase inhibitor, inhibitor of Bruton's tyrosine kinase-alpha, and BTBD26. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species. Some inhibitor of Bruton tyrosine kinase antibodies may have been used in research and have associated citations. Western Blot is a widely used application for these antibodies. ELISA and Immunohistochemistry are also common applications.