C9 and bacterial infectious disease: This pathway of neutralising bacteria by platelets also includes their bactericidal properties conditioned by complement proteins, as it has been shown that during bacterial infection an increased expression of the C3a and C5a complement receptors and the release of C8 and C9 complement components from platelets takes place and they create the C5b-C9 protein complex, or the MAC (Membrane Attack Complex), which destroys bacteria by creating transmembrane channels (34, 77).