#$%^&*AU2015224416A120151001.pdf#####H:\aar\Interwoven\NRPortbl\DCC\AAR\8378984_1 .DOC-04.09.2015 - 34 ABSTRACT The present invention relates generally to a method for the treatment and/or prophylaxis of osteoarthritis (OA). In accordance with the present invention, an antagonist of GM-CSF can be effective in the treatment of osteoarthritis. An antagonist of GM-CSF includes, but is not limited to, an antibody that is specific for GM-CSF or the GM-CSF receptor. The present invention further provides transgenic animals, such as a GM-CSF knock-out mouse, useful for testing antagonists in certain disease models.