title: Interleukin 12 exerts a differential effect on the maturation of neonatal and adult human CD45R0- CD4 T cells.
abstract: It is now recognized that IL-12 plays a predominant role in protective immunity against intracellular pathogens by promoting the development of T helper type 1 (Th1) responses. We here report the unexpected observations that IL-12 exerts differential effects on the maturation of "native" human CD4 T cells isolated from umbilical cord blood or from the blood of healthy adults. After priming in the presence of IL-12, naive cells of adult donors, defined as CD45R0- CD4+ T cells, acquire a Th1 phenotype whereas neonatal cells develop into effector cells producing high levels of IL-4 in addition to IFN-gamma. This effect of IL-12 on neonatal T cells is direct inasmuch as it is observed on highly purified CD4 T cells, however, it is not inhibited by CD8 T cells and natural killer cells. Unstimulated neonatal T cells which have been preincubated with IL-12 before the priming behave like adult T cells and acquire a Th1 phenotype after stimulation in the presence of IL-12. Given that IL-4 is a potent antagonist of Th1 responses, the finding that IL-12 promotes the maturation of neonatal T cells into IL-4 producers may explain the increased susceptibility of neonates to intracellular pathogens and should be taken into account for the development of vaccines to be used in the perinatal period.
authors.affiliation: University of Montreal, Notre-Dame Hospital Research Center, Canada.
authors.forename: U
authors.initials: U
authors.lastname: Shu
authors.forename: C E
authors.initials: CE
authors.lastname: Demeure
authors.forename: D G
authors.initials: DG
authors.lastname: Byun
authors.forename: F
authors.initials: F
authors.lastname: Podlaski
authors.forename: A S
authors.initials: AS
authors.lastname: Stern
authors.forename: G
authors.initials: G
authors.lastname: Delespesse
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D002478:Cells, Cultured; D006801:Humans; D007231:Infant, Newborn; D007371:Interferon-gamma / Q000096:biosynthesis*; D007375:Interleukin-1 / Q000494:pharmacology; D018664:Interleukin-12 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D011994:Recombinant Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014470:Umbilical Cord / Q000166:cytology
chemical_list: D007375:Interleukin-1; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12; D015847:Interleukin-4; D007371:Interferon-gamma