Abstract
These studies examine the functional changes that occur after up-regulation of FcεRIα by immunoglobulin E (IgE) for human basophils. Basophis were cultured with and without IgE antibody (PS myeloma IgE or anti-gp120-specific IgE) for 1 week and challenged with anti-IgE, anti-FcεRIα, or antigen for histamine and IL-4 secretion. There were no statistically significant changes in their response to anti-IgE or anti-receptor anti-bodies, as compared with controls incubated for the same period, whereas receptor expression increased an average of 4-fold. There was increased responsiveness to antigenic challenge, most notably at suboptimal concentrations of antigen (gp120 peptide-ovalbumin conjugate). For a 6-fold difference in cell surface density of gp120-specific IgE, there was a 2.2-fold change in antigen potency or 3-fold increases in histamine release at lower antigen concentrations. Similar results were found for secretion of IL-4. Basophil sensitivity, which is a measure of the density of antigen-specific IgE required for 50% of maximal secretion, was used to determine whether up-regulation of FcεRIα was coordinated with up-regulation of other components of the IgE-signaling pathway. The results indicated up-regulation of FcεRI is not always accompanied by changes that allow sensitivity to he maintained. These resets indicate that functional up-regulation does occur but that its magnitude may be modulated because not all components of the signaling pathway are up-regulated in a balanced manner.
Original language | English (US) |
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Pages (from-to) | 479-486 |
Number of pages | 8 |
Journal | Journal of Leukocyte Biology |
Volume | 68 |
Issue number | 4 |
State | Published - 2000 |
Keywords
- Basophils
- FcεRIα
- Immunoglobulin E
ASJC Scopus subject areas
- Immunology and Allergy
- Immunology
- Cell Biology