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Interleukin-1 activity from human cord blood monocytes
R W Wilmott1, M C Harris, K M Haines
1University of Pennsylvania School of Medicine Department of Pediatrics, Philadelphia.
Insights
Newborn monocytes show a normal interleukin-1 (IL-1) response to bacterial lipopolysaccharide (LPS). However, infants with neonatal complications exhibit heightened unstimulated IL-1 activity.
Area of Science:
- Immunology
- Neonatal Research
- Cellular Biology
Background:
- Interleukin-1 (IL-1) is a key cytokine in immune responses.
- Cord blood monocytes are crucial for neonatal immunity.
- Understanding neonatal immune function is vital for infant health.
Purpose of the Study:
- To investigate the interleukin-1 (IL-1) synthesis capacity of cord blood monocytes.
- To compare IL-1 production in neonates with and without perinatal complications.
- To assess the functional status of neonatal immune cells.
Main Methods:
- Isolation of monocytes from 27 preterm and full-term infants' cord blood.
- Stimulation of monocytes with lipopolysaccharide (LPS) from E. coli.
- Measurement of IL-1 activity using a mouse thymocyte proliferation assay.
Main Results:
- Cord blood monocyte IL-1 response to LPS was comparable to adult levels.
- Infants with perinatal complications showed significantly higher unstimulated monocyte activity.
- Stimulated IL-1 production did not differ significantly between complicated and uncomplicated neonates.
Conclusions:
- Neonatal monocytes possess an intact IL-1 response mechanism to LPS.
- Perinatal complications are associated with elevated basal IL-1 activity in neonates.
- This suggests a dysregulated immune state in neonates facing complications.
Abstract:
Cord blood monocyte synthesis of IL-1 was investigated by using a thymocyte proliferation assay. Monocytes from 27 infants ranging in gestation from 31 to 41 weeks (mean 38.9, SE 0.54) with birthweights from 1.20 to 4.31 kg (mean 3.24, SE 0.13) were isolated from cord blood; 2 x 10(5) cells/ml were plated in 15 mm wells and stimulated with 10 micrograms/ml LPS (E. coli). Control cultures contained medium alone. Supernatants were harvested after 24 hr and tested in a C3H/HeJ mouse thymocyte proliferation assay. The mean response for 27 cord monocyte samples at 24 hr was 14,142 cpm (SE 1,499), not significantly different than that for cells obtained from eight normal adult volunteers (15,137 cpm, SE 3,535). Vaginally delivered infants with perinatal complications such as amnionitis, fetal distress, or early sepsis had significantly increased unstimulated activity (5,139 vs 1,331 cpm) compared to samples from normal infants, whereas stimulated activity was not significantly different (16,219 vs 12,261 cpm). Thus, the IL-1 response to lipopolysaccharide is intact in newborn human monocytes and there is evidence of an increased unstimulated activity following neonatal complications.