Abstract: There is provided a method for detecting cathepsin K activity in bone, cartilage and/or connective tissue, the method comprising providing a biological sample, contacting the sample with an antibody having binding specificity for a neoepitope comprising EAGKPG (SEQ ID NO: 9), and detecting an immunocomplex formed between the antibody and the neoepitope, wherein presence of the immunocomplex is indicative of cathepsin K activity in bone, cartilage and/or connective tissue. There is also provided a kit for detecting cathepsin K activity in bone, cartilage and/or connective tissue.

Abstract: The present invention relates to a method for detecting cartilage degradation in a biological sample by identifying the presence of unwound type II collagen in the biological sample, said method comprising:contacting the biological sample with a monoclonal antibody which does not bind to native helical collagen but which does bind to an epitope on unwound type II collagen chains or fragments thereof, wherein said epitope has the following sequence (SEQ ID NO: 4):A-P(OH)-G-E-D-G-R-P(OH)-G-P-P(OH)-G-P; anddetecting the presence of the bound monoclonal antibody.