Consistent with the binding of EBNA3A and/or EBNA3C leading to irreversible epigenetic changes, cells become committed to a B-blast fate <12 days post-infection and are unable to de-repress p18INK4c or BLIMP-1—in either newly infected cells or conditional LCLs—by inactivating EBNA3A and EBNA3C. This evidence concerns the gene PRDM1 and infection.