Human IgE+ and IgE- are not equivalent to mouse highly cytokinergic IgE.
BACKGROUND
We have previously defined IgE+ as the IgE on basophils from a subset of highly allergic asthmatic subjects that release histamine after stimulation with histamine-releasing factor (HRF). The mechanism of IgE+ remains an enigma. Recently, there have been reports of monomeric highly cytokinergic IgEs causing mediator release, cytokine release, and phosphorylation events in cultured rodent and human mast cells in the absence of antigen.


OBJECTIVE
We investigated whether human IgE+ might exist as highly cytokinergic IgE in the human system.


METHODS
IgE+ was defined as causing greater than 10% histamine release by using HRF as a stimulus of human basophils. By definition, IgE- did not support histamine release to HRF. Once defined, serum and various purified human IgEs were used to stimulate purified human basophils or cultured human mast cells. The cells were examined for histamine release, extracellular signal-regulated kinase (ERK) phosphorylation, and IL-13 secretion.


RESULTS
We found that neither IgE+ nor IgE- induced ERK phosphorylation, histamine release, and IL-13 release from freshly isolated basophils in the absence of a specific antigen. However, human IgE alone did stimulate ERK phosphorylation in cultured human mast cells and IL-3-primed human basophils.


CONCLUSIONS
Human IgE+ is not an equivalent of the mouse highly cytokinergic IgE. However, human IgE did have effects on cultured mast cells and basophils. The effect of highly cytokinergic IgE on ERK phosphorylation and cytokine secretion might be due to the priming effect of human basophils and mast cells.
Xie
Liping
L
Johns Hopkins Asthma and Allergy Center at Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Schroeder
John T
JT
Langdon
Jacqueline M
JM
Sora-Scott
Rebecca S
RS
Kawakami
Toshiaki
T
MacDonald
Susan M
SM
D000707:Anaphylaxis / Q000276:immunology; D000818:Animals; D001491:Basophils / Q000276:immunology / Q000378:metabolism; D001854:Bone Marrow Cells / Q000276:immunology / Q000378:metabolism; D002469:Cell Separation; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis* / Q000502:physiology; D006801:Humans; D007073:Immunoglobulin E / Q000096:biosynthesis* / Q000378:metabolism* / Q000502:physiology; D008407:Mast Cells / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL
D016207:Cytokines; D007073:Immunoglobulin E