Maternal and Neonatal Antibody And T Cell Responses To SARS-CoV-2 Following Maternal Infection And/Or Vaccination

Abstract

Pregnant women and neonates are at risk for adverse SARS CoV-2 infection outcomes, but few studies have evaluated this population for adaptive immunity. Here, we utilized samples collected from pregnant women 18 years or older reporting two or more respiratory symptoms. Information about trimester of COVID positive test or history of vaccination was also collected. Maternal blood (MB) samples were collected at prenatal clinic visits, or at delivery together with the fetal cord blood (CB)(n=70 dyads). Groups were selected based on trimester of infection, vaccination only, or no history of vaccination or infection (n=9–24) and compared with banked samples from a non-pregnant, age-matched woman from the same time period (n=7–12). Data shows IgG transfer to baby irrespective of trimester of infection (n=9–24 per group). Highest levels of antibodies were observed with vaccinated, uninfected women. Functional antibodies are transferred from mother to fetus following infection and vaccination. CD4 and CD8 T-cell activation and cytokine secretion were detected in maternal PBMCs, with highly variable expression between subjects. In at least one dyad with a PCR-confirmed infection during second trimester, both maternal and cord blood samples had low level expression of anti-S, N, RBD antibodies at delivery and the cord blood mononuclear cells showed CD4 T cell activation (CD134+) and cytokine secretion (IL-2, IL-6, TNFalpha) to spike antigens. These results indicate the unusual immunity to SARS CoV-2 infection during pregnancy and suggest at least one case of a neonate with anti-viral cellular immunity. Ongoing analyses and surveillance for perinatal outcomes may reveal how these immune responses impact infant respiratory outcomes.