Low-affinity receptors for tumour necrosis factor-alpha, interferon-gamma and granulocyte-macrophage colony-stimulating factor are expressed on human placental syncytiotrophoblast.
Scatchard binding analysis has been employed to characterize expression of low-affinity receptors for tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF) by isolated human placental syncytiotrophoblast microvillous plasma membrane (StMPM) vesicles. Trophoblastic receptors for the c-kit ligand (stem cell factor) could not be identified using the same methods. No high-affinity receptors could be detected for GM-CSF or IFN-gamma, but a minority of high-affinity TNF-alpha receptors were identified. Cross-inhibition studies indicated the low-affinity receptors to be specific for each cytokine rather than to be non-specific cytokine-binding factors. Only relatively high-affinity receptors for TNF-alpha and IFN-gamma could be detected on the BeWo human choriocarcinoma cytotrophoblast cell line, whereas receptor affinity for GM-CSF was similar to that on syncytiotrophoblast. Immunohistochemical staining has confirmed expression of IFN-gamma receptor by syncytiotrophoblast: in contrast, staining for the established TNF-R1 and TNF-R2 receptors was associated mainly with placental vascular endothelium. These low-affinity cytokine receptors could reflect unique biological responses of foetal syncytiotrophoblast in the presence of local concentrations of maternal cytokine.
Hampson
J
J
Department of Haematology, University of Liverpool, U.K.
McLaughlin
P J
PJ
Johnson
P M
PM
D001667:Binding, Competitive / Q000276:immunology; D006801:Humans; D007124:Immunoenzyme Techniques; D007371:Interferon-gamma / Q000378:metabolism; D010920:Placenta / Q000276:immunology*; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000032:analysis*; D017471:Receptors, Interferon / Q000032:analysis*; D018124:Receptors, Tumor Necrosis Factor / Q000032:analysis*; D014327:Trophoblasts / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D017471:Receptors, Interferon; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma