Modification of innate immune responses to Bordetella pertussis in babies from pertussis vaccinated pregnancies

Background: Tetanus, diphtheria, acellular pertussis, inactivated polio (Tdap-IPV) vaccines administered during pregnancy protect young infants from Bordetella pertussis (B. pertussis) infection. Whilst the impact of maternal Tdap-IPV vaccination on infants' humoral response to subsequent pertussis immunisation has been investigated, little is known about any impact on innate responses. Methods: We investigated the immune response to B. pertussis in mothers and infants from Tdap-IPV-vaccinated and unvaccinated pregnancies, utilising a whole blood assay and flow cytometric phenotyping of neonatal natural killer (NK) cells, monocytes and dendritic cells. Blood was collected from mother and umbilical cord at birth, and from infants at seven weeks (one week pre-primary pertussis immunisation) and five months of age (one month post-primary pertussis immunisation). 21 mothers and 67 infants were studied. Findings: Vaccinated women had elevated pro-inflammatory cytokine responses to B. pertussis. At birth, babies of vaccinated women had elevated IL-2 and IL-12 responses, elevated classical monocyte proportions, and reduced monocyte and NK cell cytokine responses. The elevated IL-2 response persisted to seven weeks-of-age, when lower IL-10 and IL-13 responses were also seen. One-month post-primary pertussis vaccination, infants from vaccinated pregnancies still had lower IL-10 responses to B. pertussis, as well as lower IL-4. Interpretation: This study suggests that pertussis vaccination during pregnancy impacts infant cellular immune responses, potentially contributing to the modification of antibody responses already reported following primary immunisation against B. pertussis. (C) 2021 The Authors. Published by Elsevier B.V.

Automated summary

Maternal Tdap-IPV vaccination during pregnancy enhances pro-inflammatory cytokine responses to Bordetella pertussis, leading to elevated IL-2 and IL-12 responses in infants of vaccinated women at birth. Additionally, infants from vaccinated pregnancies show altered cellular immune responses, including reduced monocyte and NK cell cytokine responses at birth and lower IL-10 and IL-13 responses at seven weeks of age.