Strong Suppression by Mononuclear Leukocytes From Cord Blood of Human Newborns on Maternal Leukocytes Associated With Differences in Sensitivity to Prostaglandin E2*

ABSTRACT: We have tested peripheral mononuclear leukocytes (PML) from the cord blood of newborns, from sera of their mothers, and from sera of nonrelated nonpregnant adult women for sensitivity to suppressive exogenous prostaglandin E₂ (PGE₂). Endogenous PG production was simultaneously inhibited by indomethacin 2.8 μM. The phytohemagglutinin-stimulated (PHA-stimulated) uptake of tritiated thymidine (³H-TdR) by PML from the mothers and the nonpregnant women was suppressed by the exogenous PGE₂ at a concentration of 1.4 × 10^?8 M, 100 times less than the one required to suppress the PML from newborns (1.4 × 10^?6 M). In addition, 1.4 × 10^?7 M or less of PGE₂ reversed the suppression of neonatal PML to stimulation. The maternal PML were reversed into stimulation at 1.4 × 10^?9 of exogenous PGE₂. The amount of endogenous PGE₂ synthesized by 1 × 10⁶ fresh, nonstimulated neonatal PML according to gas chromatography-mass spectrometry assay was 5 ng (1.4 × 10^?8 M). The synthesis increased to 27 ng/10⁶ cells after 18 hours' incubation. These concentrations are similar to the ones of exogenous PGE₂ at which neonatal PML were slightly stimulated but the maternal cells were still suppressed. Preincubation for 18 h at 37°C decreased the PGE₂-induced suppression of the adult PML but did not change the response of the neonatal PML.