The antibody reacts with the N-terminal sequence ARGSVIL of aggrecan fragments produced by proteolysis at the aggrecanase site within the interglobular domain of aggrecan (aggrecan-IGD). It does not react to a significant extent with the sequence ARGSVIL contained within uncleaved polypeptide chains. ARGSVIL-Peptides produced from recombinant aggrecan-IGD in the presence of aggrecanases bind strongly to the antibody both in Western Blots (see Fig. 1) and in ELISA. ARGSVIL-Fragments derived from native aggrecan require prior deglycosylation for antibody binding.