Cysteine cathepsin S as an immunomodulatory target: present and future trends

Objective: Antigen presentation is the key to immune response. Cathepsin S plays a major role in the degradation of the invariant peptide chain associated with the major histocompatibility complex and thus affects antigen presentation. This review will focus on the recent developments made in field of cysteine cathepsins especially cathepsin S and their future prospects as a therapeutic target. Methods: Selective cathepsin inhibitors for targeting autoimmune disorders, atherosclerosis, osteoporosis, osteoarthritis and cancer are being pursued by many pharmaceutical companies. Recent publications in this field have been used as references to evaluate the current and future trends in cathepsin S inhibitors as an immunomodulatory target. Conclusions: The temporal and spatial position occupied by cathepsin S in immune presentation, gives rise to the hope that an inhibitor would impart selectivity with a lesser propensity for side effects than other immunosuppressive agents.