SPONTANEOUS AND FAS-MEDIATED APOPTOSIS ARE DIMINISHED IN UMBILICAL-CORD BLOOD NEUTROPHILS COMPARED WITH ADULT NEUTROPHILS

Apoptosis mediates neutrophil (PMN) phagocytosis and is influenced by cytokines and the Fas/Fas ligand pathway, To determine whether apoptos is of cord blood PMN differs from those of adults, cultured PMN were e valuated by morphological analysis, flow cytometry (TUNEL assay), and DNA gel electrophoresis, In addition, we studied the effect of anti-Fa s IgM or cycloheximide on induction of PMN apoptosis, Spontaneous apop tosis (24 h) was less in cord blood PMN (mean +/- SD; 29 +/- 9 vs, adu lts, 56 +/- 14%, P < 0.001), Treatment (6 h) with anti-Fas IgM induced less apoptosis in cord blood PMN (24 +/- 6 vs, adults, 63 +/- 7%, P < 0.001), as did treatment with cycloheximide (13 +/- 10 vs, adults, 55 +/- 16%, P < 0.01), These data suggest the pre-existence of proteins that inhibit apoptosis or the absence of those that promote apoptosis in cord blood PMN.