Question

A microbe has the ability to inhibit complement activation of inflammation, but it cannot inhibit complement activation of opsonization and cytolysis. Therefore, the microbe has produced inhibitors of which complement protein(s)?
a.) C5ab.) C3ac.) C3a and C5ad.) C3b and C5b

Answer 1

Answer:

The correct answer is option c.) "C3a and C5a".

Explanation:

C3a and C5a are two anaphylatoxins that mediate inflammation and are released due to complement activation of the immune system. If a microbe has the ability to inhibit complement activation of inflammation but it cannot inhibit complement activation of opsonization and cytolysis, it is likely that it has produced inhibitors of C3a and C5a. C3a and C5a are not involved in complement activation of opsonization and cytolysis, therefore if the microbe inhibits only these two proteins it will not be able to inhibit opsonization and cytolysis.