Fig. 1

Oxidative burst responses in polymorphonuclear leukocytes (PMNLs) from maternal blood (MB) and cord blood (CB) with various stimuli. a Forward and side light scatter showing the leukocyte population in whole blood; black arrowhead  = PMNLs, black arrow  = Monocytes, open arrowhead  = Lymphocytes. b Fluorescence detection by the DHR-based oxidative burst assay on flow cytometry when PMNL are stimulated by PMA, fMLP and GV.The increased fluorescence production in PMNL when stimulated by PMA results in a significant right shift in the histogram. In comparison, fluorescence intensity is modest when the PMNL is stimulated by GV. c The proportion (median, IQR) of activated PMNL showing oxidative burst from MB and CB in response to the three bacteria; GBS: MB, 99.5% (95.4–99.9%), CB, 97.5% (88.9–98.8%); GV: MB, 56.9% (21.9–92.8%), CB, 84.7% (50.8–97.5%) and E. coli: MB, 98.2% (93.9–100.0%), CB, 97.7% (89.6–99.4%). The PMNL shows more variability in generating oxidative burst in both MB and CB with GV stimulus. This difference is more marked in the MB than CB. d The percentage (median, IQR) of activated PMNL with oxidative burst in MB and CB when stimulated by PMA, fMLP and GV shows the response was highest with PMA: MB, 99.5% (98.1–100%), CB, 98.4% (92.7–99.6%), followed by GV: MB, 56.9% (21.9–92.8%), CB, 84.7% (50.8–97.5%) and fMLP: MB, 6.6% (1.3–11.2%), CB, 20.9% (14.0–35.9%). e Intensity of oxidative burst, measured as mean fluorescence intensity (mean  ±  SEM) is highest with E. coli: MB (1717 ± 220.6), CB (1971 ± 441.2) than GBS: MB (1252 ± 163.4), CB (1293 ± 217.2) or GV: MB (1026 ± 176), CB (1340 ± 243.5). f Intensity of oxidative burst is moderate with GV: MB (1026 ± 176), CB (1340 ± 243.5) in both MB and CB, compared against the high stimulus, PMA: MB (2784 ± 509.2), CB (2081 ± 584.7) and low stimulus, fMLP: MB (400.9 ± 60.47), CB (585.5 ± 78.4). (MB, n  = 10; CB, n  = 8; with GBS, MB and CB, n  = 7 each)