Complement component C9 and perforin 1 are proteins of the humoral and cell-mediated immune reponses respectively. They are both synthesised as soluble monomers but oligomerise to form cell membrane-penetrating pores which trigger target cell death. C9 pores mediate complement-initiated cytotoxicity (as the terminal event of membrane attack complex activation) and perforin 1 pores are responsible for cell-mediated cytotoxicity [1,3].

1. Peitsch MC, Tschopp J. (1991) Assembly of macromolecular pores by immune defense systems. Curr Opin Cell Biol, 3 (4): 710-6. [PMID:1722985]

2. Spicer JA, Huttunen KM, Jose J, Dimitrov I, Akhlaghi H, Sutton VR, Voskoboinik I, Trapani J. (2022) Small Molecule Inhibitors of Lymphocyte Perforin as Focused Immunosuppressants for Infection and Autoimmunity. J Med Chem, 65 (21): 14305-14325. [PMID:36263926]

3. Tschopp J, Masson D, Stanley KK. (1986) Structural/functional similarity between proteins involved in complement- and cytotoxic T-lymphocyte-mediated cytolysis. Nature, 322 (6082): 831-4. [PMID:2427956]