To investigate the importance of the mutation of the VPS4A interaction motif of pUL71 in HCMV infection, the replication kinetics of recombinant viruses TB71mutPPAA, TB71revPPAA (revertant virus of TB71mutPPAA) and TB71del315–326 in HFFs were investigated in single step kinetics using an MOI of 3 and in multi-step kinetics using an MOI of 0.01. Here, VPS4A is linked to cytomegalovirus infection.