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Bactericidal capacity of monocytes of newborn infants
Abstract:
The peripheral leukocytes of newborn infants and of adult volunteers were studied after separation of polymorphonuclear and mononuclear cells. Monocytes were identified and quantitated with the aid of histochemical staining. The in vitro killing capacity of PMN and of monocytes was assayed against Staphylococcus aureus and Escherichia coli. The monocytes of both infants and adults were significantly less active than were their PMN, but the bactericidal capacity did not differ appreciably between newborn and adult cells of either type.
Insights
Newborn and adult leukocytes show similar bacterial killing capacity. While monocytes are less effective than polymorphonuclear cells (PMNs) in both age groups, their bactericidal function is comparable between infants and adults.
Area of Science:
- Immunology
- Neonatal immunology
- Cellular immunology
Background:
- Peripheral leukocytes, including polymorphonuclear cells (PMNs) and mononuclear cells (monocytes), play crucial roles in host defense.
- Understanding the functional capacity of these immune cells in newborns is vital for assessing their early-life immunity.
Purpose of the Study:
- To compare the in vitro bactericidal activity of peripheral leukocytes from newborn infants and adult volunteers.
- To investigate differences in killing capacity between polymorphonuclear cells (PMNs) and monocytes within each age group.
Main Methods:
- Peripheral blood leukocytes were isolated from newborn infants and adult volunteers.
- Polymorphonuclear cells (PMNs) and monocytes were separated and identified using histochemical staining.
- In vitro killing assays were performed using Staphylococcus aureus and Escherichia coli to assess the bactericidal capacity of PMNs and monocytes.
Main Results:
- Monocytes from both newborns and adults exhibited significantly lower bactericidal activity compared to their respective polymorphonuclear cells (PMNs).
- The bactericidal capacity of monocytes did not show significant differences between newborn infants and adult volunteers.
- Similarly, the killing capacity of polymorphonuclear cells (PMNs) was comparable between the two age groups.
Conclusions:
- Neonatal and adult leukocytes possess comparable in vitro bactericidal capabilities against Staphylococcus aureus and Escherichia coli.
- While monocytes are inherently less bactericidal than PMNs, this functional difference is consistent across both neonatal and adult immune systems.