Cord Blood Leucocyte Expression of Functionally Significant Molecules Involved in the Regulation of Cellular Immunity
Open Access
- 1 January 2001
- journal article
- research article
- Published by Wiley in Scandinavian Journal of Immunology
- Vol. 53 (1) , 72-78
- https://doi.org/10.1046/j.1365-3083.2001.00845.x
Abstract
The cellular immune system of the newborn infant is immature and hypo‐responsive when compared with adults. The extent to which immaturity of the leucocyte function underlies hyporesponsiveness in the newborn is incompletely understood. In this study flow cytometric techniques were applied to investigate the concurrent expression of a range of surface and intracellular leucocyte functional molecules and cytokines in resting and stimulated cord and adult blood. Production of interleukin (IL)‐2 and expression of the components of its receptor, IL‐2Rα/β/γ, were investigated. No differences in the proportion of leucocytes producing IL‐2Rα and IL‐2Rγ were observed for newborns and adults. A lower proportion of T cells and natural killer (NK) cells from newborns expressed IL‐2Rβ and upregulation of expression was slower. We hypothesize that reduced IL‐2Rβ may curtail early autocrine IL‐2 activation of immune responses in the newborn. This hypothesis was supported by the observation that an increased proportion of stimulated T cells from newborns produced IL‐2 at 4 h poststimulation, but at 24 h the proportion was lower than for adult T cells. The very low levels of interferon (IFN)‐γ produced by neonatal T cells and NK cells may also be partly explained by a curtailment of early autocrine activation of T cells. Expression and kinetics of upregulation for other functional molecules were studied. CD71, HLA‐DR, tissue factor and CD152 levels were not significantly different for adults and newborns, suggesting that cord blood leucocytes, in some respects, may demonstrate functional maturity. IL‐6 secretion by stimulated monocytes was also comparable in cord and adult blood. However, IL‐1α and IL‐1β were produced by a lower proportion of monocytes from newborns than adults. Similarly, tumour necrosis factor (TNF)‐α production for monocytes and T cells was lower in cord blood. The mean fluorescence intensity for IL‐1α, IL‐1β and TNF‐α was also lower for leucocytes from cord blood. These findings are significant in relation to the inability of newborn infants to mount a febrile response to infection. The findings of lower expression of IL‐2Rβ and lower production of inflammatory cytokines IL‐1α, IL‐1β and TNF‐α is a basis for improved understanding of the immunological immaturity of leucocytes in the newborn.Keywords
This publication has 22 references indexed in Scilit:
- Methyl‐Prednisolone Up‐Regulates Monocyte Interleukin‐10 Production in Stimulated Whole BloodScandinavian Journal of Immunology, 1999
- Endogenous production of interleukin 15 by activated human monocytes is critical for optimal production of interferon-gamma by natural killer cells in vitro.Journal of Clinical Investigation, 1995
- Direct stimulation of cytokines (IL-1β, TNF-α, IL-6, IL-2, IFN-γ and GM-CSF) in whole blood. I. Comparison with isolated PBMC stimulationCytokine, 1992
- Defective Production of Interleukin-6 by Monocytes: A Possible Mechanism Underlying Several Host Defense Deficiencies of NeonatesPediatric Research, 1992
- Defective Interferon Gamma Production in Neonatal T Cells Is Independent of Interleukin-2 Receptor BindingPediatric Research, 1991
- Monoclonal antibody defining a molecule possibly identical to the p75 subunit of interleukin 2 receptor.The Journal of Experimental Medicine, 1989
- Tumor Necrosis Factor/Cachectin and Interleukin-1 Secretion by Cord Blood Monocytes from Premature and Term NeonatesPediatric Research, 1989
- Transmembrane signaling of interleukin 2 receptor. Conformation and function of human interleukin 2 receptor (p55)/insulin receptor chimeric molecules.The Journal of Experimental Medicine, 1987
- Immunologic basis for increased susceptibility of the neonate to infectionThe Journal of Pediatrics, 1986
- Immune interferon: a pleiotropic lymphokine with multiple effectsImmunology Today, 1985