Novel .beta.10 polypeptides and heterodimers thereof, and nucleic acid molecules encoding the same are disclosed. The invention also provides vectors, host cells, selective binding agents, and methods for producing .beta.10 polypeptides and heterodimeric forms thereof, specifically .alpha.2/.beta.10. Also provided for are methods for the treatment, diagnosis, amelioration, or prevention of diseases with .beta.10 polypeptides and .alpha.2/.beta.10 heterodimers or their respective binding agents.