Cytokine Signatures of Innate and Adaptive Immunity in 17DD Yellow Fever Vaccinated Children and Its Association With the Level of Neutralizing Antibody

Background. The live attenuated yellow fever (YF) vaccines have been available for decades and are considered highly effective and one of the safest vaccines worldwide. Methods. The impact of YF-17DD-antigens recall on cytokine profiles of YF-17DD-vaccinated children were characterized using short-term cultures of whole blood samples and single-cell flow cytometry. This study enrolled seroconverters and nonseroconverters after primovaccination (PV-PRNT1 and PV-PRNT2), seroconverters after revaccination (RV-PRNT1), and unvaccinated volunteers (UV-PRNT2). Results. The analysis demonstrated in the PV-PRNT1 group a balanced involvement of pro-inflammatory/ regulatory adaptive immunity with a prominent participation of innate immunity pro-inflammatory events (IL-121 and TNF-a1 NEU and MON). Using the PV-PRNT1 cytokine signature as a reference profile, PV-PRNT2 presented a striking lack of innate immunity proinflammatory response along with an increased adaptive regulatory profile (IL-41CD41 T cells and IL-101 and IL-51CD81 T cells). Conversely, the RV-PRNT1 shifted the overall cytokine signatures toward an innate immunity pro-inflammatory profile and restored the adaptive regulatory response. Conclusions. The data demonstrated that the overall cytokine signature was associated with the levels of PRNT antibodies with a balanced innate/adaptive immunity with proinflammatory/regulatory profile as the hallmark of PV-PRNTMEDIUM1, whereas a polarized regulatory response was observed in PV-PRNT2 and a prominent proinflammatory signature was the characteristic of PV-PRNTHIGH1