C3c is generated over the course of complement activation, where convertase C4b2a (classical pathway) and convertase C3bBb (alternative pathway) cleave C3 to C3b and C3a. C3b is further degraded into iC3b and C3dg/C3d. iC3b is then slowly cleaved (possibly by factor I) to form C3c (beta chain + alpha' chain fragment 1 + alpha' chain fragment 2), C3dg and C3f. C3 is crucial in the induction of tolerance generated when an antigen is introduced into immunoprivileged sites and this is exploited by pathogens and cancer cells to evade the immune system by inhibiting complement activation.