CCNB1 and infection: When treating HCMV-infected cells with the pUL97 inhibitor MBV (10 μM, added one hour before cell harvest at about five days post-infection), pUL97-cyclin B1 was efficiently and selectively inhibited (Figure 2A, lane 2), whereas no or very little impact on cyclin H and cyclin T1 interaction was measured (lanes 4 and 6; note that pUL97-cyclin T1 was close to the detection limit).