SIGNALS LEADING TO THE ACTIVATION OF NF-KAPPA-B TRANSCRIPTION FACTOR ARE STRONGER IN NEONATAL THAN ADULT T-LYMPHOCYTES

The molecular background of the defects in the immune reactivity of hu man neonates has not been fully elucidated. As the NF-kappa B transcri ption factor has a central role in the control of transcription of sev eral genes involved in immune and inflammatory responses, the authors have analysed the activation of NF-kappa B in human umbilical cord T l ymphocytes. The activity was tested by quantitating the nuclear protei ns binding to an oligonucleotide containing the consensus kappa B bind ing sequence (electrophoretic mobility shift assay). The data obtained demonstrate that phorbol dibutyrate/calcium ionophore A23187 (PDBu/io no) combination induced a clearly higher nuclear translocation of NF-k appa B in neonatal than adult T cells. This higher NF-kappa B activity was restricted to the CD4(+) T-cell subset. Analysis of the nuclear e xtracts with antibodies directed against the major components of NF-ka ppa B the p50 and RelA (p65) proteins, indicated that the composition of NF-kappa B was similar in neonatal and adult cells. These results s uggest that neonatal T cells are exposed to oxidative stress-inducing signals during delivery and/or are inherently more sensitive to NF-kap pa B activating signals than adult T cells.