Immunological detection of type II collagen degradation: Use in the evaluation of anti-arthritic therapies

Propagated Swarm rat chondrosarcoma cells, rabbit chrondrocytes (from articular cartilage of knee, shoulder and hip joints), and bovine nasal cartilage explant cultures were studied. Type II collagen (CII) and its peptide fragments were quantitated in cell medium and cell layer separately, using two previously developed assays; one assay employed a monoclonal antibody, C4F6, that reacts specifically with triple helical CII, and the other assay used an antibody, E1E5, that reacts specifically with a peptide of CII. A time-dependent increase in the content of CII and CII-derived peptides was observed in both rat and rabbit cultures. In both culture systems the majority of the native type II collagen is found associated with the cell layer (97% in rat cultures and 73% in rabbit cultures), while the major part of the CII peptides is found in the media (73% in rat cultures, 88% in the rabbit cultures). The concentration of peptides in the media reaches approximately 2 mu g mL(-1) in both chondrocyte monolayer cultures after 4 days. The CII peptide assay employing E1E5 was well suited to quantitate articular cartilage collagen degradation in explant culture. Thus it can be used to evaluate potential therapeutic agents that can modify or inhibit cartilage degradation. The assay has the added potential that it could be used in-vivo to evaluate the effectiveness of potential metalloproteinase inhibitors in animal models of osteoarthritis or in clinical trials.