title: Unbalanced Neonatal CD4(+) T-Cell Immunity.
abstract: In comparison to adults, newborns display a heightened susceptibility to pathogens and a propensity to develop allergic diseases. Particular properties of the neonatal immune system can account for this sensitivity. Indeed, a defect in developing protective Th1-type responses and a skewing toward Th2 immunity characterize today the neonatal T-cell immunity. Recently, new findings concerning Th17, regulatory helper T-cell, and follicular helper T-cell subsets in newborns have emerged. In some circumstances, development of effector inflammatory Th17-type responses can be induced in neonates, while differentiation in regulatory T-cells appears to be a default program of neonatal CD4(+) T-cells. Poor antibody production, affinity maturation, and germinal center reaction in vaccinated neonates are correlated with a limiting expansion of TFH lymphocytes. We review herein the factors accounting for and the implications of the unbalanced neonatal helper T-cell immunity.
authors.affiliation: Institut d'Immunologie Médicale, Université Libre de Bruxelles , Gosselies , Belgium.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Debock
authors.affiliation: Institut d'Immunologie Médicale, Université Libre de Bruxelles , Gosselies , Belgium.
authors.forename: Véronique
authors.initials: V
authors.lastname: Flamand
keywords: T helper subsets; Th17; Th2-biased response; Tregs; defective Th1 response; follicular helper T-cells; vaccine