Respiratory syncytial virus (RSV) and the human parainfluenza viruses (PIV) are causes of significant morbidity and mortality among infants each year. We are now advancing SeVRSV, a Sendai virus based Jennerian vaccine for human PIV-1 and a recombinant vaccine for RSV. SeVRSV expresses RSV F and induces immunity that protects against RSV in small animals and non-human primates. Immune responses persist systemically and in the respiratory tract, which ensures that pathogens can be blocked at their point-of-entry. One concern surrounding pediatric vaccines is that maternal antibodies may obstruct vaccine efficacy. We therefore designed a cotton rat maternal antibody model to test SeVRSV. First, to define the levels of maternal antibodies typical of the vaccine's intended target population, we titered antibodies from approximately 100 human infants. Then, by passive transfer techniques, we matched these titers in animals. Intranasal vaccination in test animals was followed by the measurement of de novo PIV-specific and RSV-specific antibodies, and cotton rat challenge with RSV to measure protection. In models using polyclonal or monoclonal antibody products with specificities for PIV and/or RSV, the SeVRSV vaccine protected against RSV challenge. Data suggest that SeVRSV will not be inhibited by maternal antibodies in the clinical setting, and encourage rapid development of the vaccine for protection of human infants from PIV and RSV.
- Copyright © 2013 by The American Association of Immunologists, Inc.