Transplacental Antibody Transfer of Respiratory Syncytial Virus Specific IgG in Non-Human Primate Mother-Infant Pairs

Abstract

One approach to protect new-borns against respiratory syncytial virus (RSV) is to vaccinate pregnant women in the last trimester of pregnancy. The boosting of circulating antibodies which can be transferred to the foetus would offer immune protection against the virus and ultimately the disease. Since non-human primates (NHPs) have similar reproductive anatomy, physiology, and antibody architecture and kinetics to humans, we utilized this preclinical species to evaluate maternal immunization (MI) using an RSV F subunit vaccine. Three species of NHPs known for their ability to be infected with human RSV in experimental challenge studies were tested for RSV-specific antibodies. African green monkeys had the highest overall antibody levels of the old-world monkeys evaluated and they gave birth to offspring with anti-RSV titers that were proportional to their mother. These higher overall antibody levels are associated with greater durability found in their offspring. Immunization of RSV seropositive AGMs during late pregnancy boosts RSV titers, which consequentially results in significantly higher titers in the vaccinated new-borns compared to the new-borns of unvaccinated mothers. These findings, accomplished in small treatment group sizes, demonstrate a model that provides an efficient, resource sparing and translatable preclinical in vivo system for evaluating vaccine candidates for maternal immunization.

Respiratory Syncytial Virus Maternal Vaccination in Infants below 6 Months of Age: Meta-Analysis of Safety, Immunogenicity, and Efficacy

“…Similarly, the F-based RSV vaccine was shown to be immunogenic to ameliorate antibody levels in recipients, including non-pregnant healthy women [24] and specific populations, e.g., the elderly and children [25]. A growing body of research in vivo also demonstrated how passive immunization of the offspring by administering F-based RSV jab to the dams is helpful to promote MatAbs, in both the dams and their offspring [26][27][28].…”

We are all on the same team

“…Acquisition of maternal antibodies protects against most severe RSV infection during the first weeks after birth. Passive immunity via transplacental antibodies is critically dependent on gestational age at delivery with little transfer in children born before 28-32 weeks of gestation 94 .…”