Characterizing the cellular and humoral immune responses to Tdap during pregnancy compared to non-pregnant controls

Abstract

Abstract Maternal Tdap vaccination during pregnancy is recommended to protect infants from pertussis, pre-vaccination. However, it is unclear whether maternal immune responses improve following Tdap booster. We present analysis of immune responses pre- and post-Tdap booster, of pregnant women (Pw) primed by whole cell vaccines, who received Tdap booster during pregnancy, compared to Tdap boosted non-pregnant women (NPw). Tdap antigen specific serum antibody reactivity and avidity increased following booster in both groups. Reactivity and avidity were higher in NPw compared to Pw. Activation-induced marker assay of peripheral blood revealed that pertussis specific Tmem cells increased following Tdap booster in Pw and NPw. After Tdap booster, the percentage of CD4+CD25+OX40+ T cells was approximately 2.5-fold higher in NPw. In contrast, the proportion of CD4+CD25+PDL1+ T cells post-booster were 3-fold higher in Pw compared to NPw, suggesting that Tdap booster may elevate Tregs in Pw. Interim analysis suggests that booster vaccination increases immune responses, although the magnitude and phenotype differ between Pw and NPW. Antibody function, race related immune profiles, and detailed phenotyping of T cell responses are in progress.