Pregnant women exhibit altered humoral and cellular immune responses after vaccination

2026-07-16T02:58:53Z https://www.fdr.uni-hamburg.de/oai2d

oai:fdr.uni-hamburg.de:18769 2026-06-16T08:44:23Z user-uhh

true 3.1 UHH.FDR 10.25592/uhhfdm.18769 Christopher Urbschat Department of Obstetrics and Prenatal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany Petra Arck Department of Obstetrics and Prenatal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany Anke Diemert Department of Obstetrics and Prenatal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany Pregnant women exhibit altered humoral and cellular immune responses after vaccination Universität Hamburg 2026 2026-06-11 https://www.fdr.uni-hamburg.de/record/oai:fdr.uni-hamburg.de:18769 10.25592/uhhfdm.18768 Restricted Access Raw data files regarding the following publication entitled: Pregnant women exhibit altered humoral and cellular immune responses after vaccination Abstract Background During pregnancy, maternal immune tolerance is mounted to protect the semi-allogenic fetus from rejection. This tolerance reduces the maternal response to pathogens, heightening the risk of severe infections. Consequently, vaccination against pathogens such as influenza and SARS-CoV-2 is recommended to protect both mother and child. Nevertheless, there is limited understanding of the vaccine-induced immune responses in women within the unique immunological state of pregnancy. Our study compares the immune responses of pregnant and non-pregnant women to a model vaccine, SARS-CoV-2, which was administered to a population with no prior exposure to the pathogen. Methods SARS-CoV-2-naïve pregnant and non-pregnant women (n=31/groups) received the mRNA vaccine Comirnaty. Six weeks post-vaccination, SARS-CoV-2-specific total IgG, IgA, IgM, and neutralizing IgG titers, IgG subclasses, and IgG Fc N-glycosylation were analyzed. Single-cell RNA sequencing (scRNASeq) of T and B cells from vaccinated pregnant and non-pregnant women was performed. Results We detected significantly lower serum levels of neutralizing SARS-CoV-2-specific IgG antibodies, altered IgG subclass distribution, and more complex Fc N-glycan patterns in pregnant women. scRNASeq revealed reduced signaling in pathways crucial for vaccine response, notably in blood-derived plasmablasts and CD4 T effector memory cells, affecting CD40, IL-4, and IL-13 pathways. Conclusions Our study shows that pregnancy influences B cell subsets and plasmablast function, leading to more complex IgG glycosylation upon vaccination. We identified gene-level immune-modulatory alterations affecting T- and B-cell interactions in pregnant women, also relevant to e.g., infections. Our findings inform about the potential effectiveness of other vaccines during pregnancy beyond SARS-CoV-2, which is particularly relevant, since the range of new vaccines to be administered during pregnancy continues to expand, candidates include Group B Streptococcus, cytomegalovirus, and malaria. Linked files: File: "Urbschat_etal_2026_IgG_titers_raw_data" exhibits all raw data used for figure 1 (B-D) to calculate titers. File: "Urbschat_etal_2026_Glycosylation_raw_data" exhibits all raw data used for figure 2 and supplementary figure 1 and 2.