Assessing the Effects of Maternal PFAS Exposure on the Immune Response to Tdap Vaccination and Placental IgG Transfer to the Fetus in Rabbits

Abstract

Per- and polyfluoroalkyl substances (PFAS) pollution is a global health concern affecting people of all ages and sexes. Humans are exposed to PFAS through several routes, including contaminated food, drinking water, dermal absorption, indoor dust, and air pollution. Among emerging PFAS compounds, perfluorobutanesulfonic acid (PFBS) has gained attention due to its increasing detection in water systems and bioaccumulation. Elevated PFAS levels correlate with reduced antibody concentrations for vaccinated diphtheria and tetanus in children. However, their impact on maternal immune responses to vaccination and the efficiency of placental IgG transfer remain largely unexplored. This study investigates whether maternal PFAS exposure affects the transfer of Tdap vaccine-specific IgG antibodies across the placenta to the fetus and the expression of the IgG transfer receptor (FcRn) in placental tissues.45 nulliparous, 6-month-old female New Zealand White rabbits were randomly allocated to five groups: control water (deionized drinking water), low-dose PFAS mixture, high-dose PFAS mixture, low-dose PFBS, or high-dose PFBS groups for 30 days before pregnancy and across gestation. Rabbits received two doses of the Tdap vaccine, with the initial dose administered seven days before gestation (GD-7) and a booster dose given on gestational day 11 (GD11). Dams and their kits underwent necropsy on gestational day 25 (GD25), with serum samples collected at GD-7 and GD25. ELISA was used to measure Tdap vaccine antibodies, with titers determined by a 3-fold change between GD-7 and GD25. Immunoglobulin G transfer efficiency is calculated as the ratio of blood levels of IgG in kits to their dams taken from GD25. Our study found that placental transfer efficiency of IgG antibodies from dams to kits did not change significantly among PFAS mixture or PFBS exposed groups compared with controls regardless of sex. These data align with the qPCR results, showing no significant differences in FcRn gene expression in placentas between the PFAS-treated and control groups or PFBS-treated and control groups. Conclusion, our data showed no evidence that PFAS mixtures or PFBS alone reduce vaccine effectiveness during gestation, thereby not lowering protection for offspring against neonatal diseases.