Infectious Disease
Transplacental transfer of viral IgG antibodies is variable across viral pathogens Shannon C. Conrey* Shannon Conrey Conrey Conrey Conrey Conrey Conrey Conrey Conrey Conrey Conrey Conrey Conrey Case Western Reserve University School of Medicine
Transplacental transfer of maternal antibody provides immune protection to the infant in early life, when the infant’s immune system is immature. We examined maternal transfer of antibodies against 10 viral pathogens by comparing IgG concentrations in paired third-trimester maternal to cord sera.
PREVAIL (Cincinnati, OH 2017-2020) collected maternal serum at enrollment (≥34 weeks gestation) and cord serum at birth. Assays quantified IgG antibodies against endemic coronaviruses (OC43, NL63, HKU1, 229E), influenza (H1N1, H3N2, B-Victoria, B-Yamagata), RSV, and rotavirus. Maternal to cord concentration Spearman correlations were calculated. The maternal transfer ratio (MTR) was derived by dividing the cord by the maternal concentration and compared by geometric means (GM) using ANOVA and pairwise t-tests (Holms corrections). The proportion of participants with efficient transfer (MTR >1) by virus were compared using Χ2. Wilcoxon Rank Sum and Fisher’s Exact tests compared demographic and health factors between those we defined as highly efficient (≥8 efficiently transferred) and not highly efficient.
This analysis included 85 dyads with completed IgG assays for all 10 viruses. Maternal to cord correlations ranged from r=0.79 for OC43 to r=0.95 for H1N1 and H3N2 (all p<0.001). The GM MTR for rotavirus (1.44) differed from HKU1 (1.81, p=0.004), OC43 (1.83, p=0.002), B-Victoria (1.75, p=0.04) and B-Yamagata (1.76, p=0.03). Proportion of efficient transfer was ≥92% for all viruses except rotavirus (79%, p<0.001). Most (93%, 79/85) had highly efficient transfer; 65% (55/85) transferred all 10 antibodies efficiently. Child birthweight differed between highly (3.3 (3.1, 3.6) kg) and not highly efficient (2.8 (2.6, 3.1) kg, p=0.02).
Transplacental transfer of IgG antibody is typically efficient but differs by pathogen. Understanding passively acquired immunity should also consider the quality of transferred antibodies and pathogen-specific reasons for differences in efficiency.
