%0 Journal Article %T Plasmacytoid dendritic cells engagement by influenza vaccine as a surrogate strategy for driving T-helper type 1 responses in human neonatal settings. %+ Régulation Immunitaire et Vaccinologie %+ Unit of Innate Defense and Immune Modulation %+ Virus et Immunité %+ Department of Obstetrics and Gynecology %+ Maternité Port-Royal [CHU Cochin] %+ CIC Cochin Pasteur (CIC 1417) %A Zhang, Xiaoming %A Casartelli, Nicoletta %A Lemoine, Sebastien %A Mozeleski, Brian %A Azria, Elie %A Le Ray, Camille %A Schwartz, Olivier %A Launay, Odile %A Leclerc, Claude %A Lo-Man, Richard %< avec comité de lecture %@ 1528-8366 %J The Internet Journal of Infectious Diseases %I Internet Scientific Publications, LLC %V 210 %N 3 %P 424-34 %8 2014-08-01 %D 2014 %R 10.1093/infdis/jiu103 %M 24558121 %Z Life Sciences [q-bio]Journal articles %X The elicitation of T-helper type 1 (Th1) cellular immunity to eradicate intracellular pathogens is a challenging task because of the interleukin 12 (IL-12) deficit observed in early infancy. Screening cord blood responses to various pediatric vaccines and Toll-like receptor (TLR) agonists for innate responses and CD4(+) T-cell differentiation. We identified that nonadjuvanted inactivated trivalent influenza vaccine (TIV) was able to cosignal T cells for the production of interferon γ (IFN-γ) in a neonatal setting. This process includes the mobilization of neonatal plasmacytoid dendritic cells (pDCs) as antigen-presenting cells (APCs) that efficiently engage Th1 cells in an IL-12-independent but type I IFN-dependent manner. In addition, cord blood pDCs efficiently cross-presented antigen to CD8(+) T cells. Importantly, activation by TIV mainly requires TLR7; however, R848/TLR7- and CpGB/TLR9-activated pDCs, which poorly produced IFN-α, induce neonatal Th2 responses. TLR pathway engagement in pDCs is necessary but not sufficient for a successful neonatal Th1 outcome. We provide evidence of a mature and functional neonatal immune system at the level of APCs and T cells and propose to implement the IFN-α/IFN-γ axis in pediatric vaccination as a surrogate for the defective IL-12/IFN-γ axis. %G English %L pasteur-01108113 %U https://pasteur.hal.science/pasteur-01108113 %~ PASTEUR %~ UNIV-PARIS5 %~ UNIV-PARIS7 %~ RIIP %~ CNRS %~ APHP %~ RIIP_PARIS %~ UPEC %~ ATP-IMMUN %~ UNIV-PARIS %~ ANR %~ FRM %~ CIC1417