Answer:
membrane attack complex (MAC)
Explanation:
Membrane attack complex is formed on the surface of invading pathogen by the host's immune system. It forms transmembrane channels in the membrane of pathogen and disrupts it via complement mediated lysis. In this process, series of reactions take place in cascade which allows the host to destroy the foreign particle.
It has been reported that some pathogens can evade complement mediated lysis by inhibiting the formation of membrane attack complex due to their thick cell wall. Example: S.Aureus . Mainly gram positive bacteria are able to inhibit MAC.