Multiple Pathways for Regulating Complement Activation Limit the Potential Damage

Multiple Choice

Multiple pathways for regulating complement activation limit the potential damage caused by complement deposition on host cells or caused by the spontaneous activation of complement proteins in the plasma. Genetic deficiencies in these mechanisms often lead to chronic inflammatory diseases, but in some cases can paradoxically lead to increased susceptibility to bacterial infections. This latter outcome may occur because:

A) Complement regulatory proteins have dual functions in inhibiting and promoting complement activation.
B) Uncontrolled complement activation leads to the depletion of serum complement proteins.
C) The inhibition of the membrane attack complex by complement regulatory proteins normally leads to enhanced activation of the early steps of the complement pathway.
D) Complement regulatory proteins normally cause the rapid depletion of plasma complement factors.
E) Uncontrolled complement activation recruits the majority of phagocytic cells, leaving few remaining to fight infections in the tissues.