Complex sentence: DC Comics, Marvel Comics, and other CCA sponsors began publishing comics intended for adult audiences, without the CCA seal, and comics labeled for "mature readers" under imprints such as DC's Vertigo and Marvel's Epic Comics were not submitted to the CCA.
Split into simpler sentences: DC Comics, Marvel Comics, and other CCA sponsors began publishing comics intended for adult audiences, without the CCA seal. Comics published under new "mature readers" imprints such as Vertigo Comics and Epic Comics were not submitted to the CCA.