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Updated: Aug 13, 2026
07:22
Basophil Activation Test for Allergy Diagnosis
Published on: May 31, 2021
Staphylococcal Extracellular Complement-Binding Protein Induces IL-4 Production in Murine Basophils
Haruka Sakakibara1,2, Shion Kamada1,2, Rikuto Iwata1
1Department of Molecular and Cellular Health Sciences, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan.
Microbiology and Immunology
|August 11, 2026
Summary
Staphylococcus aureus exotoxin Ecb activates basophils to produce IL-4, independent of complement inhibition. This finding reveals Ecb
Area of Science:
- Immunology
- Microbiology
- Molecular Biology
Background:
- Staphylococcus aureus causes infections and allergic inflammation.
- S. aureus exotoxins are classified by structure.
- Previous work showed certain exotoxins activate innate immune cells.
Purpose of the Study:
- Investigate triple-helix bundle-containing S. aureus exotoxins.
- Determine if Extracellular complement-binding protein (Ecb) activates mast cells and basophils.
Main Methods:
- Tested Ecb's effect on murine bone marrow-derived mast cells and basophils.
- Assessed IL-4, IL-6, and IL-13 production.
- Used C3-binding-deficient Ecb mutant and Src kinase inhibitor Dasatinib.
Main Results:
- Ecb induced IL-4 and IL-6 in basophils, but not mast cells.
- Ecb activated basophils independently of complement inhibition.
- Src family kinase activity was required for Ecb-induced basophil activation.
Conclusions:
- Ecb is a novel basophil-specific activator, inducing IL-4 production.
- Ecb contributes to immune evasion and allergic inflammation.
- Ecb activation of basophils is IgE-independent and requires Src kinases.
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