Project 5

HCMV vaccine produced from BAC-MVA that blocks epithelial and fibroblast entry.

The culmination of years of study on the original fibroblast (Fibro) pathway of human cytomegalovirus (HCMV) entry was a clinical trial in which a formulated gB vaccine was repeatedly administered to HCMV-negative women and 50% protection against primary infection was found. We have reproduced this success using RhCMV-negative RM by demonstrating 50% protection against a virulent RhCMV challenge, using an modified vaccinia Ankara virus (MVA) vaccine composed of RhgB and the tegument protein Rhpp65. We hypothesize that to further improve vaccine success; efficient inhibition of CMV entry into Epi/EC will be required. We recently published that vaccination of RhCMV-negative RM with RhUL128C-MVA produced high titer neutralizing antibodies (NAb) that inhibit virulent RhCMV natural isolates from infecting Epi/EC and Fibro, confirming RhUL128C function. Based on these novel results in the RhCMV/RM model, we constructed an HCMV counterpart to RhUL128C in bacterial artificial chromosome (BAC)-MVA, and the reconstituted MVA virus used to vaccinate BALB/c mice generated NAb to prevent in vitro HCMV infection of Epi/EC. In future studies, H-UL128C-MVA will be used to vaccinate RM and properties of NAb generated against the pentamer complex in sera and saliva from vaccinated and control groups will be assessed in preventing natural HCMV isolate infection of ARPE-19 cells. Avidity assays of post-vaccination sera will be assessed using urea denaturation after binding to pentamer containing lysates. We will choose a regimen for inhibition of two HCMV entry pathways by including vaccines expressing H-UL128C and HCMV pp65/gB subunits either as two individual vaccines or a single multiple insert form. The formulation and regimen will be selected based on generation of superior NAb avidity and titers that interfere with in vitro HCMV infection of ARPE-19 cells and Fibro. The anticipated result of these studies will be an HCMV-based subunit vaccine ready for clinical development.
Felix Wussow, Ph.D.
Post-doctoral Fellow, Division of Translational Vaccine Research

Flavia Chiupessi, Ph.D.
Post-doctoral Fellow, Division of Translational Vaccine Research
Peter A Barry, Ph.D.
Vice Chair for Research, Department of Pathology and Laboratory Medicine, UC Davis
Principal Investigator of the UC Davis consortium site