Maternal #Influenza A Virus #Infection Induces Antiviral and Immune Dysregulation in the #Placenta and #Fetus Without Vertical Transmission
Abstract Influenza A virus (IAV) infection during pregnancy is associated with stillbirth and preterm birth , possibly by disrupting placental and fetal immunity . To investigate this, pregnant pigtail macaques were inoculated with IAV [A/California/07/2009 (H1N1)] and examined at necropsy 5 days post-infection (N=11) versus uninfected controls (N=16). Stillbirth occurred in 18% of infected pregnancies but not in controls. While vertical transmission was not observed, low levels of viral RNA were detected in two placentas . Maternal IAV infection was associated with increased placental IL-1β and IFN-β levels and an upregulated type I interferon and integrated stress transcriptional response. Fetuses exposed to IAV had greater frequencies of innate immune cells in lymph nodes and CD4+ T cells in lungs . These results suggest that placental and fetal immune environments undergo immune activation independent of the severity of maternal lung infection. Influenza vaccination during pr...