Cyotchines exert their action by binding with specific receptor sites on the cell membrane. This causes a secondary release/production of a regulator protein(s) which modifies the cell. see microvet.arizona.edu/Courses/MIC419/Tutorials/Cytokines.html
What I was trying to say in my original post was AT3 was an inhibitor of serine proteases. SPs are involved in many regulatory functions. Since AT3 can effect the action of the SPs there is an excellent chance it may be of clinical use in other disease processes.