CCNB1 and infection: However, surprisingly, at 24 h post MVM infection, when 70–80% of cells were infected, we observed that the cyclin B1 that was present displayed a nuclear localization in approximately 90% of infected cells (see Figure 6B), and in many cells showed co-localization with MVM NS1 in APAR replication centers (Figure 6A, panels a and b).