Abstract

Antibody-Mediated Neonatal Protection Against Respiratory Syncytial Virus

Shamir Jacobino, , University Medical Center Utrecht

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections in young infants. For unknown reasons RSV infections rarely occur in the first weeks after birth. We hypothesized that in utero acquisition of RSV-specific antibodies from amniotic fluid into the lungs contributes to early viral protection. Therefore, we measured the presence of RSV neutralizing antibodies in 28 normal amniotic fluid samples. We detected RSV neutralizing activity in all these samples and demonstrate that antibodies specifically recognized the prefusion conformation of the RSV F protein. In vivo, we show that monoclonal RSV neutralizing antibodies protected mice against RSV infection for at least one week. Moreover, exposure of the airways of mice to human amniotic fluid resulted in IgG-dependent protection against RSV infection. Combining human and mouse studies, we provide the first evidence to suggest that specific amniotic fluid antibodies are sufficient to protect the neonate against life-threatening RSV infection in the first weeks of life.