Related Experiment Videos
IL-3, IL-5, and granulocyte-macrophage colony-stimulating factor potentiate basophil mediator release stimulated by
E U Sarmiento1, B R Espiritu, G J Gleich
1Department of Immunology/Microbiology, Rush Medical College, Chicago, IL 60612, USA.
Abstract:
We have examined the potential of IL-3, IL-5, and granulocyte-macrophage (GM)-CSF to enhance basophil activation by eosinophil granule major basic protein (MBP). Preincubating basophil-containing mononuclear cells with 0.01 to 10 ng/ml IL-3 or IL-5 for 15 min at 37 degrees C caused a concentration-dependent enhancement of histamine release stimulated by 1.5 microM MBP. Statistically significant enhancement was evident at 1 ng/ml and was maximal at 10 ng/ml. Preincubation with GM-CSF similarly enhanced MBP-induced histamine release. A 10- to 15-min preincubation with IL-5 maximally increased the level of MBP-stimulated histamine release. Preincubation of cells with 10 ng/ml IL-3 or IL-5 reduced the MBP concentrations required for histamine release by three- to fourfold and enhanced the rate of MBP-induced histamine release. MBP-stimulated histamine release before or after cytokine priming was independent of cytotoxicity as measured by 51Cr release. Consistent with a direct action of the cytokines on basophils, flow cytometric analysis demonstrated the presence of IL-3 and GM-CSF receptors on basophils. MBP also stimulated low levels of leukotriene C4 (LTC4) release from basophils of 84 to 99% purity, and experiments using enriched (18-63%) basophil preparations demonstrated that preincubation with IL-3, IL-5, and GM-CSF also potentiated MBP-stimulated leukotriene C4 release up to threefold in parallel with histamine release. These results indicate that IL-3, IL-5, and GM-CSF may contribute to the pathogenesis of allergic and other disorders characterized by eosinophilia in part through potentiation of basophil mediator release stimulated by MBP.
Insights
Interleukin-3 (IL-3), IL-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF) enhance basophil activation by major basic protein (MBP). These cytokines potentiate histamine and leukotriene C4 release, contributing to allergic disease pathogenesis.
Area of Science:
- Immunology
- Cell Biology
Background:
- Basophils play a key role in allergic inflammation.
- Eosinophil granule major basic protein (MBP) is a potent activator of basophils.
- Interleukins (ILs) and colony-stimulating factors (CSFs) are critical regulators of immune cell function.
Purpose of the Study:
- To investigate the synergistic effects of IL-3, IL-5, and GM-CSF on basophil activation by MBP.
- To determine the impact of these cytokines on mediator release from basophils.
Main Methods:
- Basophil-containing mononuclear cells were preincubated with varying concentrations of IL-3, IL-5, or GM-CSF.
- Cells were subsequently stimulated with MBP to measure histamine and leukotriene C4 release.
- Flow cytometry was used to detect cytokine receptors on basophils.
Main Results:
- IL-3, IL-5, and GM-CSF demonstrated a concentration-dependent enhancement of MBP-induced histamine release.
- Cytokine preincubation reduced the required MBP concentration and increased the rate of histamine release.
- These cytokines also potentiated MBP-stimulated leukotriene C4 release.
- IL-3 and GM-CSF receptors were confirmed on basophils.
Conclusions:
- IL-3, IL-5, and GM-CSF significantly enhance basophil activation and mediator release stimulated by MBP.
- These findings suggest a role for these cytokines in the pathogenesis of allergic disorders associated with eosinophilia.