Polypeptides are provided. Antibodies or antigen binding domains are provided which bind such polypeptides. Also provided are methods of obtaining an antibody that binds tumor necrosis factor (TNF)-related apoptosis-inducing ligand (“TRAIL”) Receptor-2 (TR-2) comprising administering at least one of such polypeptides to an animal and obtaining an antibody that binds TR-2 from the animal. Antibodies reactive with TR-2 are provided. Also provided are cells producing antibodies reactive with TR-2, pharmaceutical compositions comprising antibodies reactive with TR-2, methods using antibodies reactive with TR-2, and kits comprising antibodies reactive with TR-2. Also provided are methods of decreasing or preventing binding of an antibody to TR-2 by administering such a polypeptide.