Evaluation of Measles Vaccine Virus as a Vector to Deliver Respiratory Syncytial Virus Fusion Protein or Epstein-Barr Virus Glycoprotein gp350

Mok, Hoyin; Cheng, Xing; Xu, Qi; Zengel, James R; Parhy, Bandita; Zhao, Jackie; Wang, C. Kathy; Jin, Hong

We also examined replication of EZ vectored RSV F and EBV gp350 in vivo by using real time qRT-PCR since differential in growth kinetics of recombinant measles virus may explain the difference in antibody responses. However, we were not able to detect measles genomes in PBMC isolated from whole blood 24 hours post vaccination. This may be attributed to the low copies of measles virus circulating in the blood or the time point used to measure measles kinetics in vivo was not optimal. In conjunction, we have examined replication of EZ vectors in PBMC of rhesus macaques ex vivo to determine if insertion of the foreign gene affected replication of these viruses in PBMC. PHAactivated PBMC cells were infected with rMV at MOI of 1.0 and growth kinetics were determined for 7 days. The peak titer of the recombinant viruses containing RSV F or EBV gp350 were only 0.5 log 10 lower than rEZ (data not shown), indicating the vectored vaccine could infect rhesus cells. We also investigated genetic stability of the insert by serially passaging the recombinant viruses in Vero cells 10 times and did not find the loss of the inserted gene expression as reported previously [61, 62] .