The disclosure relates to protease-binding agent specific for a protease. The agent may be an antibody capable of specifically binding and inhibiting a protease, such as a P1-Arg-specific protease. The disclosure also provides methods of producing, and compositions comprising the subject agent. Methods and kits related to the protease-binding agent find use in protection against, detection, diagnosing, treating cancer and infections due to pathogens containing active proteases.
