Surface and gene expression of immunoglobulin E receptors on mast cells and mast-cell numbers in interleukin-4-gene knockout mice.
We quantified immunoglobulin E (IgE) on peritoneal mast cells of interleukin-4 (IL-4)-gene knockout (-/-) mice and wild-type (+/+) controls using a cytofluorometric method, and examined the expression of IgE receptors, estimated by quantifying the total binding of IgE on the mast cells of IL-4 (-/-) mice. The mast cells of IL-4 (+/+) mice, identified and measured using microscope fluorometry, had a fluorescence intensity five to six times higher than that of non-mast cells, while the mast cells obtained from IL-4 (-/-) mice had fluorescence intensities within the range of those of non-mast cells. Two weeks after an infection with Nippostrongylus brasiliensis, the fluorescence intensity of the mast cells of IL-4 (+/+) mice increased to a level about twice as high as that before immunization. However, no significant increase after infection was observed in IL-4 (-/-) mice. Furthermore, the mast cells of IL-4 (-/-) mice did not bind IgE when incubated with IgE at concentrations that saturated IgE receptors on the mast cells of wild-type controls, thereby indicating that the expression of IgE receptors on mast cells was impaired in the IL-4-deficient mice. Using a reverse transcription-polymerase chain reaction, we found gene expression of all three subunits (alpha-, beta- and gamma-chains) of the IgE receptor in IL-4 (-/-) like that in IL-4 (+/+) mice. The results thus suggest that the binding of IgE may be essential to induce the translation of mRNA to IgE-receptor proteins. We also observed that there were about twice as many peritoneal mast cells in the IL-4 (-/-) mice as there were in the IL-4 (+/+) mice, in both immunized and non-immunized animals. This was unexpected in view of previous findings suggesting that IL-4, in concert with stem cell factor and IL-3, stimulates the proliferation and differentiation of mast cells in vitro.
Chen
X J
XJ
Department of Pathology, Institute of Laboratory Medicine, Sahlgrenska University Hospital, Göteborg, Sweden.
Lycke
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Enerbäck
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D000818:Animals; D002452:Cell Count; D015870:Gene Expression / Q000276:immunology; D007073:Immunoglobulin E / Q000378:metabolism; D015847:Interleukin-4 / Q000235:genetics / Q000276:immunology*; D008297:Male; D008407:Mast Cells / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009559:Nippostrongylus; D010529:Peritoneal Cavity / Q000166:cytology; D012333:RNA, Messenger / Q000235:genetics; D017455:Receptors, IgE / Q000235:genetics / Q000378:metabolism*; D017206:Strongylida Infections / Q000276:immunology
D012333:RNA, Messenger; D017455:Receptors, IgE; D015847:Interleukin-4; D007073:Immunoglobulin E