Deficient interferon-gamma receptor-mediated signaling in neonatal macrophages.
OBJECTIVE
To describe functional and molecular characteristics of interferon-gamma (IFN-gamma) activation in neonatal mononuclear phagocytes (monocytes and macrophages).


RESULTS
Exposure of cord and adult macrophages to IFN-gamma gave quantitatively different results in Candida killing, as well as in release of superoxide anion (O2-). At concentrations of 100 U ml(-1) IFN-gamma, maximal increase in these functions with adult macrophages was achieved, whereas no enhancement of killing and O2- release by cord macrophages could be detected. Expression of IFN-gamma receptors was comparable on cord and adult cells and specific binding of [125I]IFN-gamma to cord monocytes and macrophages was even higher compared with adult cells. By flow cytometry, elements of IFN-gamma receptor-mediated signaling in cord and adult monocytes and macrophages were studied. Monoclonal antibodies against the native form of the signal transducer and activator of transcription-1 (STAT-1) revealed comparable expression of this protein in cord and adult macrophages. However, STAT-1 phosphorylation in response to IFN-gamma was significantly decreased in neonatal monocytes (p < 0.05) and macrophages (p < 0.01) compared with adult cells.


CONCLUSIONS
These data suggest deficient cytokine receptor signaling in neonatal mononuclear phagocytes exposed to IFN-gamma.
Maródi
L
L
lmarodi@jaguar.dote.hu
D000328:Adult; D000367:Age Factors; D002176:Candida albicans / Q000276:immunology; D016022:Case-Control Studies; D002478:Cells, Cultured; D003470:Culture Media; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D006801:Humans; D007111:Immunity, Cellular / Q000502:physiology; D007231:Infant, Newborn / Q000276:immunology*; D007371:Interferon-gamma / Q000494:pharmacology*; D008262:Macrophage Activation / Q000276:immunology*; D008297:Male; D009000:Monocytes / Q000276:immunology; D010587:Phagocytosis / Q000276:immunology; D017471:Receptors, Interferon / Q000096:biosynthesis* / Q000276:immunology*; D012680:Sensitivity and Specificity; D000096743:Interferon gamma Receptor
D003470:Culture Media; D007371:Interferon-gamma; D017471:Receptors, Interferon; D000096743:Interferon gamma Receptor