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

Since cotton rats are partially permissive to MV, MV vectored vaccine was further evaluated in rhesus macaques. Rhesus macaque is fully permissive to measles virus infection and the infected monkeys develop symptoms similar to those experienced by humans, such as skin rash, fever and conjunctivitis [47] . This monkey model was used in the neurovirulence testing of MV vaccine [57] . In addition, since rhesus macaques could be infected with human measles virus, the breeding colony is commonly vaccinated with MV. This allowed us to examine the effect of prior vaccination on vectored measles and mimic our target populations that either have maternal antibodies or have measles vaccination history. rEZ and rEZ expressing gp350 and sF3 induced a good level of antibody response to PBMCs measles virus irrespective of their sero-status to MV. The antibody response was slightly lower in magnitude than what were observed in the cotton rats as the dose per kg used in the rhesus was ~ 90 times lower than in cotton rats. The antibody response to the F and gp350 inserts was much lower in rhesus macaques. A previous report showed that two doses of MV-HIV gp140 at 5x10 6 TCID 50 (25 times higher dose than our study) induced a robust Ab response towards HIV gp140 in monkeys [10] . However, three doses of 10 4 TCID 50 (1/15 our dose) of MV vectored HBV surface antigen induced a very low response in monkeys [14] . Thus, the low humoral responses to the vectored inserts in rhesus macaques may be due to a lower dose used in this study.