NOD1 and NOD2 expression and function in very preterm infant mononuclear cells

Aim
To evaluate mononuclear cell expression and function of the cytosolic nucleotide-binding oligomerization domain-containing receptors, NOD1 and NOD2, in very preterm and full-term infants.
Methods
NOD1 and NOD2 gene and protein expression in very preterm infants, term infants and healthy adult, cord and peripheral blood mononuclear cells (C/PBMC) were quantified using qPCR and flow cytometry. Cytokine responses of purified infant and adult monocytes to NOD1- and NOD2-specific agonists were assessed using a multiplex immunoassay (Bioplex).
Results
NOD1 and NOD2 were expressed by a range of infant and adult mononuclear cell types, including T- and B cells, with highest expression in classical (CD14++CD16−) and intermediate (CD14++CD16+) monocytes. NOD1 and NOD2 expression levels by monocytes from very preterm infant were similar to those in term infants or adults. Monocyte production of TNFα, IL-6 and IL-1β induced by activation of NOD1 and NOD2 was similar between very preterm infants, term infants and adults.
Conclusion
Monocyte expression and function of NOD1 and NOD2 in very preterm infants are intact and comparable/equivalent to term infants and adults. Functional deficiencies in monocyte NOD signalling pathways are unlikely to contribute to the increased susceptibility to bacterial sepsis in preterm infants.