In the context of SIRS, inhibiting C5 cleavage in baboons with Escherichia coli-induced sepsis with a macrocylcic compound RA101295 induced a prompt effect in reducing proinflammatory responses as early as 2 h post sepsis induction in terms of reduced circulatory levels of C3b, C5a and soluble C5b–9 and attenuated damage of the lung and kidney25. Here, C3 is linked to systemic inflammatory response syndrome.