+C3b is a crucial fragment born from the cleavage of [C3](/wiki/C3), central to the [Complement System](/wiki/Complement_System). This protein acts as a molecular flag, tagging pathogens for removal and initiating a cascade of immune responses.
+## See also
+- [Complement System](/wiki/Complement_System)
+- [Opsonization](/wiki/Opsonization)
+- [Immune System](/wiki/Immune_System)
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