A Parainfluenza Virus Vector Expressing the Respiratory Syncytial Virus (RSV) Prefusion F Protein Is More Effective than RSV for Boosting a Primary Immunization with RSV
Bo Liang, Yumiko Matsuoka, Cyril Le Nouën, Xueqiao Liu, Richard Herbert, Joanna Swerczek, Celia Santos, Monica Paneru, Peter L. Collins, Ursula J. Buchholz, Shirin Munir
Abstract
Immune responses to RSV in infants can be reduced due to immunological immaturity and immunosuppression by RSV-specific maternal antibodies. In infants and young children, two infections with wild-type RSV typically are needed to achieve the titers of RSV-specific serum antibodies and protection against illness that are observed in adults. Therefore, a boost might substantially improve the performance of live pediatric RSV vaccines presently being developed. Hamsters and African green monkeys received a primary intranasal infection with RSV and were given a boost with RSV or a parainfluenza virus (PIV) vector expressing RSV fusion protein engineered for enhanced immunogenicity. The RSV boost was highly restricted but induced a significant increase in serum RSV-neutralizing antibodies. The PIV vectors replicated efficiently and induced significantly higher antibody responses. The use of an attenuated PIV vector expressing RSV antigen to boost a primary immunization with an attenuated RSV warrants further evaluation.